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This paper presents a comprehensive three-dimensional numerical investigation of horizontal square anchors embedded in geogrid-reinforced sand. Prior experimental studies have demonstrated notable enhancements in anchor uplift capacity when placed below geogrid reinforcement in soil. However, these results are limited to small anchor plates tested in laboratory conditions with over-reinforced sand. In contrast, this study focuses on large field-scale anchors and explores the influence of anchor width, embedment depth, reinforcement size, stiffness, and tensile strength on uplift capacity. The findings reveal that the optimal size for geogrid reinforcement is three times the anchor width. A diminishing improvement in uplift capacity with increasing anchor width was observed. Additionally, deeper anchor embedment reduces the uplift capacity improvement in geogrid-reinforced sand. The geogrid reinforcement is found to be more efficient in the case of shallow anchors placed in loose sand. The major contribution of this paper lies in the response analysis of large anchors and providing a better understanding of the uplift mechanism in geogrid-reinforced sand. • This paper presents a three-dimensional numerical investigation of large field-scale horizontal square anchors embedded in geogrid-reinforced sand. • The findings reveal that the optimal size for geogrid reinforcement is three times the anchor width (B) in contrary to the 5B value reported in the previous literature. • A diminishing improvement in uplift capacity with increasing anchor width was observed. • Deeper anchor embedment reduced the uplift capacity improvement in geogrid-reinforced sand. • The geogrid reinforcement is found to be more efficient in the case of shallow anchors. [ABSTRACT FROM AUTHOR]

Bipolar plates (BPPs) and membrane electrode assemblies (MEAs) are the key components for proton exchange membrane fuel cells (PEMFCs), they are alternately arranged to construct a compact stack with high power generation. This stacking method may introduce several issues, such as the difficulties in maintenance, imprecise assembly and sealing. This paper presents a novel integrated packaged single fuel cell that employs titanium metal bipolar plates to construct a short stack with superior sealing performance and working reliability. To predict the performance of integrated packaged single cell, numerical model was developed to analyze the mass transfer of O 2 , H 2 and H 2 O within the cell, revealing a uniform distribution of reactants and current. A short stack was manufactured with 10 layers of single cells, it retains excellent sealing properties and consistent output across a range of pressure conditions, with a leakage rate deviation lower than 0.03 mL/(min·cell) and membrane current density variation less than 5%. Finally, the electrochemical performance of the integrated packaged short stack was tested, its maximum power is 886.67 mW/cm2. It can achieve a rated output power of 169.14 W and an energy density of 1684.97 mW/cm3. Thus, our developed short stack has high energy utilization efficiency for power generation, and is anticipated to provide a durable power source for drones, robots and new energy vehicles. • An integrated packaged single fuel cell short stack based on titanium metal polar plates was proposed. • Numerical model of single cell was established, simulation on gas molar concentration and current density distribution was conducted. • A 10-layer integrated short stack was fabricated, assembly stress and polarization tests verified its good sealing performance. [ABSTRACT FROM AUTHOR]

• Cathodes consisting of carbon paper, electrode, and electrolyte are reconstructed. • An improved LBM model is developed for modeling the discharge process. • Time-dependent local porosity of cathode is considered by the proposed model. • The spatial distribution of electrode on O 2 diffusion and discharge are studied. The discharge process of lithium–oxygen battery (LOB) is a highly complicated multi-physics coupling phenomenon. Moreover, the cathode morphology presents a complex multi-scale structure with pore size ranging from nanometers to micronmeters, and plays a crucial role in determining the discharge performance. In this work, the cathodes consisting of carbon paper, electrode material, and electrolyte are first numerically reconstructed using a two-step reconstruction method considering the multi-scale morphology. A lattice Boltzmann model with an improved partial bounce-back scheme is proposed for modeling the discharge process given that the electrode porosity changes with the progress of discharge. The effects of micron-scale electrode spatial distribution on the O 2 diffusion and LOB discharge performance are investigated. Results show that the increment of the electrode dispersion degree increases the O 2 diffusion resistance due to the increase of electrolyte-electrode specific interface area. A large local electrode load near O 2 inlet leads to a high O 2 diffusion resistance and low O 2 concentration owing to the large specific interface area and electrode volume. Cathodes with the minimum electrode load and maximum electrode dispersion degree present the optimal specific capacity of LOB. However, the specific capacity first increases significantly and then slightly decreases with the increase of local electrode load. [ABSTRACT FROM AUTHOR]

River water irrigation is used to reduce soil salinity in the reed fields of the Shuangtai Estuary Wetland in Northeast China to improve the reed quality for paper industry; however, quantitative effects of this approach have not yet been investigated. In this study, the effect of irrigation was investigated by conducting comprehensive field observations and numerical simulations, and the necessary irrigation water volume was determined. The field observations included determination of (1) the relation between surface soil salinity and reed yield; (2) vertical profile of soil salinity before and after the irrigation period; and (3) variation of depth and salinity of the standing water during irrigation and the rate of rainwater interception by reed leaves. Our findings suggested that (1) the reed yield decreased remarkably when the surface soil salinity exceeded 5‰ and (2) irrigation could reduce salinity to below this level. From our observations, water budget in the irrigated reed fields was evaluated. A numerical model was constructed to simulate the salinity reduction process by assuming that the salinity flux across the ground surface was proportional to the salinity difference between the standing water and the surface soil. The model parameters were calibrated using the results of observation (3) such that the model successfully reproduced the observed time series of standing water salinity. A series of numerical experiments were performed using the model to determine the irrigation water volume necessary for sufficient soil salinity reduction. The results suggested that soil salinity reduction depended greatly on rainfall during the reed growth period. Further, an initial irrigation depth of about 20 cm was sufficient for lowering the salinity to 5‰ even during rainfall shortage that occurred every 10 years on an average. Replacing the saline standing water before intensive rainfall events with rainwater was found to be an effective approach to lower the surface soil salinity. [ABSTRACT FROM AUTHOR]

The catalyst support structure has a significant influence on the performance of the methanol steam reforming (MSR) microreactor for in-situ hydrogen production. Triply period minimal surface (TPMS) structures are emerging as an attractive option as porous MSR catalyst supports owing to their excellent specific surface area, smooth surface and highly interconnected pores. This paper develops a numerical model of the sheet TPMS unit structures with catalyst coating to investigate the flow and reaction characteristics for hydrogen production of MSR reaction. The P, G, and D curved surface structural models were constructed with different porosities. The numerical results indicated that the P curved surface structure with the porosity of 90% had the lowest pressure drop of 0.15 Pa and the highest permeability of 6.31 × 10−9 m2, while the G curved surface structure always demonstrated excellent flow performance within the porosity range of 50–90%. The D curved surface structure exhibited the best reaction performance with hydrogen production exceeding P and G curved surface structures by about 23% and 78% respectively. Furthermore, the performance differences between the two flow phases of the sheet TPMS structures were investigated for the bicontinuous characteristic. The flow phases of the G curved surface structure demonstrated the best consistency in flow and reaction performances. Finally, the optimal design of the sheet, network, and multi-unit heterogeneous TPMS structural catalyst supports was discussed. • A numerical model of the TPMS structures with catalyst coating was developed. • The flow and reaction characteristics of the TPMS structures were studied. • The performance of two flow phases in the TPMS structures were compared. [ABSTRACT FROM AUTHOR]

The study of unsteady combustion modes and, in particular, the deflagration-to-detonation transition, is of particular importance for the aerospace industry. Knowledge of the basic mechanisms, as well as the criteria for the development of detonation, helps to control this process in the framework of its applications for novel propulsion devices and safety issues. In this paper, a series of calculations are carried out in order to distinguish the role of channel geometry (planar or circular) in the flame dynamics at all the stages of acceleration prior to the deflagration-to-detonation transition. The combustion of a stoichiometric acetylene-oxygen mixture diluted with nitrogen is considered. It is established that in channels with a circular cross-section, the flame front is stretched and the combustion process evolves up to the transition to detonation, in accordance with the experiment. At the same time, in planar channels (slits), the primary flame acceleration leads to the establishment of a quasi-stationary mode. The peculiarities of the compression and rarefaction waves evolution in the cylindrical and planar geometry are responsible for such a difference between the flame dynamics in channels of different geometry. The detonation onset takes place via the formation of a "chocked flame" structure characterized by permanent joint compression and acceleration of the combustion. As well as in experiments the deflagration-to-detonation transition occurs exactly at the flame front. • Numerical study of flame acceleration in C 2 H 2 / O 2 / N 2 mixtures using reduced chemistry. • The effect of the channel geometry on the flame acceleration is demonstrated. • Flame dynamics in planar and circular channels is described. • Detailed analysis of deflagration-to-detonation transition is provided. [ABSTRACT FROM AUTHOR]

This paper reports numerical modeling of the prototype geosynthetic reinforced soil (GRS) walls corresponding to four centrifuge models that have different toe restraint conditions. The development of the interface stresses and displacements at wall toe during wall construction is investigated to understand how the toe carries load in the GRS walls with a practical toe structure. The numerical results show good agreement with the data from the centrifuge modeling. For the GRS walls with a leveling pad embedded in foundation soil, the shear resistance at the facing block-leveling pad interface acts as the toe resistance to counterbalance a portion of horizontal earth load, while the leveling pad-foundation soil interface play no role in wall performance because the soil passive resistance in front of the leveling pad inhibits the development of the shear stress and displacement on this interface. For the GRS walls with an exposed leveling pad, it is the leveling pad-foundation soil interface that works for carrying the earth load because the wall is more likely to slide along this weaker interface. The contribution of the toe to load capacity depends on the shear strength of the effective toe interface that contributes to the resistance against the earth load. • Paper reports numerical modeling of four prototype GRS walls corresponding to the centrifuge models at a specific centrifugal acceleration. • The effect of toe restraint conditions on the development of interface stresses and displacements at wall toe during wall construction was investigated. • How the toe carries load in the GRS walls with a practical toe structure was analyzed. [ABSTRACT FROM AUTHOR]

• Numerical modeling of thermoacoustic devices can be classified into 1-D linear and 2-D/3-D non-linear models. • Linear thermoacoustic models lose their utility, in the high amplitude and high frequency regime. • CFD modeling has proven to be an effective tool in capturing the nonlinearities associated with standing wave thermoacoustic devices. • Flow dominance in a 2-D plane inside SWTADs has allowed the performance evaluation of these devices utilizing 2-D CFD models. • CFD modeling of standing wave thermoacoustic devices primarily focus on stack and the region around it. Global environmental concerns have brought the challenge of developing renewable energy technologies to cope up with the world energy needs. Thermoacoustic devices present themselves as a viable alternative to replace conventional refrigeration and power systems due to their minimal carbon footprint. These devices involve complex flow physics encompassing transient phenomenon and conversion of acoustic and thermal energies for their efficient performance. With the rapid advancement in computational capabilities, extensive numerical work is carried out to gain detailed understanding of the thermoacoustic devices. In this paper, a detailed review of the numerical modeling techniques that have been applied in the field of Standing Wave Thermoacoustic Devices (SWTAD) is carried out. At first, a brief review of analytical method is presented and the need for numerical modeling is highlighted. Numerical modeling techniques ranging from simplified linear to detailed Computational Fluid Dynamics (CFD) models are reviewed in detail. Model configurations, capabilities and tools developed and utilized so far in the research area are summarized. Challenges associated with SWTAD and applications modeled using CFD are discussed. The paper concludes with some useful recommendations regarding the numerical modeling of thermoacoustic devices. [ABSTRACT FROM AUTHOR]

Today, the exact determination of the parameters of the fracturing of oil and gas fields is of great practical importance. Therefore, an important role is played by computer modeling of the seismic responses from cracks, which correspond to fractured zones actually occurring in nature in terms of the distribution of fracture lengths, positions and rotation angles. Thus, the development of an algorithm aimed at solving this problem plays an important role. In this paper, we have presented the developed algorithm for the placement of cracks in a fractured zone with given geological parameters, such as distribution of lengths, opening, angle of inclination of cracks. The application of this algorithm makes it possible to use in further calculations a geological fractured zone model that is as close as possible to real oil and gas-filled reservoirs. The paper presents the results of test calculations using the grid-characteristic computational method to model wave field scattered on the fractured zone. [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive Virtual Reality (VR) based framework for visualizing numerical simulations of geophysical flows in a realistic and immersive manner. The framework allows integrating output data from various mesh-based Eulerian numerical models into a VR environment, enabling users to interact with and explore the terrain and geophysical flows through the VR experience. Three case studies, including a snow avalanche, quick clay landslide, and flash flood in Norway, demonstrate its versatility. The VR environment offers intuitive menus and user interactions, allowing users to read flow depth and velocity values, facilitating a direct link between numerical data and their visual representation. This framework can reshape geophysical flow hazard identification and disaster management by integrating physics-based numerical modeling results into VR Environments, thus enhancing knowledge dissemination among experts, the general public, non-expert stakeholders, and policymakers. The paper also highlights challenges and opportunities identified during the integration, guiding future developments. • A framework that integrates numerical simulations of geophysical flows into VR. • The framework is versatile across different geophysical flow types and numerical models. • Real time visualization of numerical simulation results is still a challenge. • The framework has a potential for disaster preparedness and emergency training. [ABSTRACT FROM AUTHOR]

Here we present our workflow, numerical models and results of the spatial distribution of chalcopyrite mineralization under the different porosity and permeability conditions of the host rocks of the Shaxi deposit. During the numerical modeling research, we tried to coupling heat transfer, fluid flow, material migration, mineralization reaction, and their coupling with porosity and permeability of rock. The results show that the porosity and permeability of the host rocks play a significant role in the mineralization of porphyry-type systems. The chemical properties of the strata restrict significantly on mineralization intensity and spatial extent rather than affecting the depth of mineralization. This paper also indicates that the numerical modeling method employed in this study can be used to predict the mineralization depth and spatial location of deep concealed porphyry-type deposits, aiding research in deep-seated mineral exploration. [Display omitted] • The porosity and permeability of the host rocks play a significant role in the mineralization of Shaxi porphyry-type deposit. • The chemical properties of the strata restrict significantly on mineralization intensity and spatial extent rather than affecting the depth of mineralization. • The numerical modeling may be used to predict the mineralization depth and spatial location of deep concealed porphyry-type deposits. The Shaxi porphyry-type Cu-Au deposit is located in the northwestern outer margin of the Luzong volcanic basin, which is situated in the Middle-Lower Yangtze River Metallogenic Belt (MLYRMB), Eastern China. It is a large porphyry-type Cu-Au deposit with confirmed copper resources exceeding 1 Mt and gold resources exceeding 40 tons. Previous studies have extensively investigated the genesis, controlling structures, geochemical characteristics, fluid evolution, alteration zone, and ages of mineralization and host rocks in this deposit. However, research on the influence of the physical and chemical properties of the host rocks on the mineralizing processes has not been explored in detail. This study employs the finite element method to apply numerical modeling of multiple physical and chemical fields, interlinking heat transfer, fluid flow, material migration, mineralization reaction, and their coupling with porosity and permeability of rock, to investigation of the influence of different porosities, permeabilities, and chemical properties of the host rocks on the mineralizing processes in the Shaxi deposit. The results show that the porosity and permeability of the host rocks play a significant role in the mineralization of porphyry-type systems. The different porosity and permeability of the intrusions and strata control the depth, the mineralization intensity, the morphology of the ore bodies, and the spatial location of the mineralization center. The chemical properties of the strata significantly restrict the mineralization intensity and horizontal spatial rather than affecting the depth of mineralization. Furthermore, the formation of skarn-type deposits may require a longer period of time than that of porphyry-type deposits under the same mineralization conditions and ore grade. This paper also indicates that the numerical modeling method employed in this study can be used to predict the mineralization depth and spatial location of deep concealed porphyry-type deposits, aiding research in deep-seated mineral exploration. [ABSTRACT FROM AUTHOR]

Stainless steel exhibits strain hardening characteristics under cyclic loading, hence presenting significant potential for application in seismic design. However, the current stainless steel structural design code fails to account for this beneficial effect in the cross-section classification. Given the scarcity of research about the behavior of structural stainless steel members under cyclic stress, this paper establishes the preliminary finite element model for the austenitic stainless steel (EN 1.4301) H-section. Firstly, finite element model validation of the existing cyclic tests on stainless steel members from literature was performed, followed by numerical analyses of a total of 370 beam and beam-columns members with different axial compression ratios and plate width-thickness ratios, and subsequently evaluated the cross-section classifications specified in prEN 1993-1-4, AISC 370 and CECS 410 through extensive parametric studies. The results indicate that the current design codes are conservative in the provisions for cross-section classification because they neglect the influence of plate interactions and material strengthening effects during cyclic loading. In this paper, limit and generalized expressions for austenitic stainless steel H-section with different axial compression ratios and cross-section classes under cyclic loading about major-axis are proposed. Additionally, the effect of material strengthening on cross-section classification under cyclic loading is examined. • Classification criteria for austenitic stainless steel H-section under cyclic loading about major-axis are studies. • Cross-section classification criteria according to EC3, AISC 370 and CECS 410 design codes are evaluated. • A new cross-section classification criterion for H-section under cyclic loading is proposed. • Effect of material strain hardening on cross-section classification under cyclic loading is discussed. [ABSTRACT FROM AUTHOR]

An advanced enhanced geothermal system (EGS) is capable of unlocking many thousands of megawatts of power in hot dry rocks, and the fracture configuration is a critical factor influencing its efficiency. A flyover-crossing fracture (FCF) configuration for EGS was proposed in this paper, to enhance heat transfer between the working fluid and reservoir and thus the productivity of EGS. A 3D transient thermal-hydraulic model was established to analyze the heat extraction of the FCF-EGS, and the effects of intersection angles of the FCF on the heat and mass transfer as well as the productivity of the EGS were examined. The FCF-EGS was found to bring higher production temperature and thermal power output than the conventional double-horizontal-well EGS during a 30-year heat recovery period, and the heat extraction capacity of the FCF-EGS was found to increase with the intersection angle. It was also found that the FCF with a 90°cross-angle has the best heat extraction performance, with the output thermal power increased by 5.12% compared to the conventional double-horizontal-well EGS, due to the enhancement of heat transfer between the working fluid and rock. Although this fracture system requires more investment in fracturing and larger pressure in production, the increase in heat production far outweighs this input. This study provides a novel potential fracture configuration for exploiting HDR geothermal energy. [ABSTRACT FROM AUTHOR]

This paper presents an experimental and numerical study of the combustion of isolated n ‑butyl acetate droplets in the standard atmosphere. Numerical simulations are reported using a model that incorporates unsteady gas and liquid transport, variable properties, and radiation. Three skeletal mechanisms of n ‑butyl acetate, derived from a large detailed mechanism comprised of 819 species and 52,698 reactions, were used in the numerical simulations to evaluate the influence of the kinetic mechanism on burning. The reduced mechanisms comprised 212 species and 5413 reactions, 157 species and 3089 reactions, and 105 species and 1035 reactions. The numerical model did not include soot formation, though qualitatively mild sooting was noted only for droplets larger than 0.7 mm. The numerical predictions were in good agreement with experimental measurements of droplet and flame diameters. Flame extinction was numerically predicted which was attributed to a decrease of the characteristic diffusion time relative to the chemical time as droplet burned. Effects of initial droplet diameter on the evolution of maximum gas temperature (T max) and peak mole fractions of CO 2 and CO are also examined numerically. [ABSTRACT FROM AUTHOR]

Non-stationary modes of gaseous fuel combustion are of paramount importance for their efficient and safe usage in the space industry. The paper analyzes experimental and numerical data on the early stages of flame propagation in channels of different widths. It is demonstrated that there is a self-similar behavior of flame development at least at the considered stages. Qualitatively flame acceleration proceeds exponentially in channels of different widths, though the particular acceleration increment is inversely proportional to the width of the channel. Exponential acceleration is related to the positive feedback between the flame and flow dynamics, while the previous stage is associated mainly with the flame propagation induced by the expansion of combustion products. Based on the analysis of experimental data, one can estimate both the time instant at which the exponential stage starts and the increment of exponential acceleration, which in turn depends unambiguously on the normal burning rate. As a result, a novel technique for normal burning rate determination with the use of a channel reactor can be proposed. • Flame evolution in a channel goes from spherically expanding to finger flame modes. • Channel width defines exponential increment of finger flame velocity increase. • Flame acceleration process proceeds similarly in channels of different widths. • Transition point between flame modes can be used to estimate laminar burning velocity. [ABSTRACT FROM AUTHOR]

The objective of this paper is to model the residual stress generation mechanisms induced during the finish turning of a fillet radius on a 15-5PH steel shaft. The model, based on the 3D thermo-mechanical equivalent loading method, is used to predict the continuous variation of residual stresses resulting from the continuous variation of the machined sections in the fillet radius. Finally, experimental tests are carried out to compare the numerical results with the residual stress measurements made by X-ray diffraction in some positions. [ABSTRACT FROM AUTHOR]

Composite pressure vessels are highly promising components of solid rocket motor casing, yet it has long been plagued by burst risk of dome section. Although current advances via the addition of composite layers can enhance dome strength, the weight redundancy still restricts the lightweight implementation. To this end, this paper presents an innovative contour-driven collaborative design for dome section, which helps suppress burst risk and avoid redundant weight due to composite layer thickening. Numerical burst assessment reveals that the pole size engenders a failure competition between pole and equator, indicating that rational utilization of this competition paves a feasible way for dome reinforcement. Besides, the burst risk is further suppressed by collaborative design between polar opening radius, polar boss size, and aspect ratio of ellipsoidal dome. Notably, it is concluded that greater polar boss size effectively reduces the stress concentration near pole, and rational manipulation of dome aspect ratio ensures compatible deformation near equator. More interestingly, we offer a collaborative design methodology to reinforce dome with various polar opening radii without thickening composite layers. This unique contour-driven collaborative design opens new avenues for simultaneous implementation of burst risk suppression and lightweight construction of composite pressure vessels. [ABSTRACT FROM AUTHOR]

• The post-fire behavior of S890 UHSS CHS beam–columns was investigated. • Eighteen post-fire eccentric compression tests were conducted. • FE models were developed and validated against test results and then used to perform parametric studies. • The room temperature design rules were assessed for their applicability to S890 UHSS CHS beam–columns after fire exposure. An experimental and numerical modeling program was carried out to investigate the post-fire structural behavior and residual resistances of S890 ultra-high strength steel (UHSS) circular hollow section (CHS) beam–columns after exposure to elevated temperatures and presented in this paper. Eighteen CHS beam–column specimens were tested, with heating, soaking and cooling of specimens, post-fire tensile coupon tests as well as measurements of initial global geometric imperfections firstly performed. Finite element (FE) models were developed and validated against the available experimental results, and then adopted for generating further numerical data covering a wider spectrum of member lengths, cross-sectional dimensions and loading combinations to expand the data pool. Owing to the absence of design provisions for steel structures after exposure to elevated temperatures, the relevant ambient temperature design interaction curves outlined in the current European, American and Australian specifications are evaluated for their applicability to S890 UHSS CHS beam–columns after exposure to elevated temperatures, with post-fire material properties used. The assessment results revealed that the codified provisions in the European, American and Australian specifications can lead to safe but slightly conservative resistance predictions for S890 UHSS CHS beam–columns after exposure to elevated temperatures, except for a few unsafe data points (for the elevated temperature of 800 °C) predicted by the Australian standard. [ABSTRACT FROM AUTHOR]

Determining material parameters is essential for understanding the physical properties of fiber-reinforced concrete (FRC), enhancing the design process, and optimizing costs. This paper presents a deterministic numerical model of FRC beams under three-point bending tests (TPBT), with an emphasis on the failure analysis. This model aims to replicate TPBT and address the challenge that comes with direct measurements of FRC parameters, especially in the context of failure mechanisms. It integrates analytical solutions and explicit parameters to describe the bending and failure behavior, while mitigating computational demands in parameter identification due to the complex heterogeneous nature of the material. Laboratory tests were conducted to record key parameters and served as a foundation for the model development and validation of its predictive capabilities. The generated simulated data from the predictive numerical model were then utilized as input for an inverse analysis based on the Levenberg–Marquardt method. The inverse analysis demonstrated high accuracy, with parameter convergence typically within 3 to 7 iterations and errors reduced to less than 2%. Model verification was performed by comparing the results obtained from the inverse analysis with the data obtained from laboratory tests, confirming the model's effectiveness in accurately predicting FRC failure behavior. [Display omitted] • Formulated a novel model for FRC beams under three-point bending conditions. • The model simulates both pre-peak and post-peak stages of bending behavior. • Laboratory tests linked single fiber pull-out with FRC beam bending in modeling. • Performed sensitivity analysis to assess the new model's capacity. • Used Levenberg-Marquardt inverse method for material parameter extraction. • Presented the influence of material parameters on crack progression rates. [ABSTRACT FROM AUTHOR]

The present study deals with melting in a geometry suitable for Latent-Heat Thermal Energy Storage (LHTES) systems, which are of importance for future industrial installations utilizing solar energy or waste heat. The intrinsically high thermal resistance of phase-change materials (PCM) can be remedied by taking advantage of close contact melting (CCM), where the solid phase is separated from a hot surface by only a thin liquid layer. The basic CCM takes place on a horizontal flat surface, but during the last decade its application in various finned LHTES units has been demonstrated experimentally and analyzed numerically. Specifically, the configuration studied in the present work is relevant to a horizontal double-pipe concentric storage unit with a longitudinally finned inner tube. While this rather simple geometry has been extensively studied in the past, the present work is completely novel in its demonstration and analysis of simultaneous close-contact melting on two generally asymmetric surfaces created by the longitudinal fins. A unique experimental apparatus is introduced, based on the so-called 'Mercedes' configuration of the fins. It is designed transparent, allowing for real-time observation of melting sequences. Close-contact melting is achieved by supplying heat to the outer shell of the unit: the solid phase is detached from the shell and moves, by translation and rotation, in the liquid phase. The results from these experiments demonstrate the feasibility of CCM on two asymmetric walls within this system, hinting at the potential for optimizing the melting rate by utilizing a larger portion of the extended surface for CCM. A key component of this study is the development of a reliable numerical approach, which goes beyond the limitations of widely-applied enthalpy-porosity method and combines the general enthalpy formulation, convective heat transfer and general rigid body motion that includes rotation. Therefore, a new numerical model has been devised, using an in-house code realized in MATLAB. A full set of the governing conservation equations is solved using a finite-difference framework, integrated with advanced numerical methods for the fluid-solid interaction and an enthalpy formulation for the phase change process. The model is validated carefully, and then numerical studies are conducted to elucidate the melting process. The present paper presents a further proof of the special role that close-contact melting (CCM) can play in properly designed thermal energy storage units and finned systems in general. It is demonstrated that the fins, when properly designed and oriented, can induce CCM in their vicinity, contributing to a very significant increase in the melting rate, which reflects charging of the unit. [ABSTRACT FROM AUTHOR]

This paper investigates the inelastic buckling of imperfect unanchored cylindrical steel tanks subjected to seismic loads. A pushover-based seismic analysis was conducted considering the impulsive hydrodynamics pressures on the wall and base plate of the tank. Material and geometric nonlinearities were considered in the seismic analysis of the tanks. Three types of imperfections were analyzed: imperfections due to impacts, imperfections located at the bottom of the tank wall, and imperfections with the first buckling mode shape. The buckling analysis was performed for two tank geometries (one slender and one broad), and the effect of the imperfections was correspondingly evaluated. The considered imperfection amplitudes were established according to the New Zealand seismic design code for storage tanks. Additionally, amplitudes that exceed the normative limit were evaluated to further analyze the sensitivity to imperfection. The analysis revealed that geometric imperfections reduce the peak ground acceleration needed to induce buckling failure. Specifically, the critical peak ground acceleration for the slender tank decreased from 0.195 g to 0.180 g for the slender tank and from 0.600 g to 0.535 g for the broad tank. This buckling capacity reduction due to geometric imperfections were about 8 % and 11 % for the slender and the broad tanks, respectively. • Impact of geometric imperfections, within and beyond normative limits, on storage tanks analyzed using finite element models. • Three types of geometric imperfections are explored. • Geometric imperfections can reduce the buckling capacity of tanks by approximately 10 %. [ABSTRACT FROM AUTHOR]

This paper presents experimental and numerical investigations on the flexural performance of concrete-filled double skin steel tubular (CFDST) beams utilizing recycled aggregate concrete (RAC). Six beam specimens were tested under pure bending. The failure modes, moment versus deflection relations, and strain distributions were analyzed. A finite element (FE) model was established and validated, enabling a parametric study to examine the influence of key parameters. Furthermore, the flexural bearing capacity calculation method specified in the current code for CFDST beams, originally intended for normal concrete members, was evaluated for its applicability for RAC counterparts. The findings indicated that CFDST beams using RAC exhibited ductile behaviour under bending, achieving effective confinement between the steel tubes and sandwiched RAC. The assessment revealed that the calculation method in the current code yielded reasonably accurate yet conservative predictions for the flexural bearing capacity of CFDST beams filled with RAC. • The bending tests of CFDST beams using RAC were conducted to obtained the flexural behaviour. • The validated FE model was applied to analyze the influence of key parameters on the flexural performance. • The applicability of the calculation method in the current code was evaluated. [ABSTRACT FROM AUTHOR]

This paper presents experimental and numerical investigations into the post-fire local buckling behavior and residual resistances of S890 ultra-high strength steel (UHSS) circular hollow section (CHS) under combined compression and bending. The physical testing was firstly conducted and encompassed heating, soaking and cooling of specimens, as well as post-fire tensile coupon tests, measurements of initial local geometric imperfections and eccentrically loaded stub column tests. Then, finite element models were developed and validated with reference to the experimental observations and then adopted for parametric analyses to derive additional numerical data, considering various cross-section dimensions and loading combinations. As a result of the lack of design provisions for ultra-high strength steel structures after exposure to elevated temperatures, the applicability of the relevant ambient temperature design interactive curves given in the current European, American and Australian standards to post-fire S890 UHSS CHS under combined compression and bending was assessed, with post-fire material properties used. The assessment results showed that all design standards exhibited conservative and scattered predictions of residual resistances for S890 UHSS CHS under combined compression and bending at ambient temperature and after exposure to elevated temperatures. The American specification provided more precise predictions of residual failure loads for non-compact and slender (Class 3 and 4) sections than the Eurocode and Australian standard, due to the accurate compression and bending endpoints. In comparison to the American and Australian specifications, the Eurocode resulted in more precise results in predicting residual failure loads of compact (Class 1 and 2) sections, owing to the accurate compression and bending endpoints as well as the nonlinear design interaction curve. • Post-fire behavior of S890 UHSS CHS under combined compression and bending was investigated. • Eighteen post-fire eccentric compression tests were conducted. • FE models were developed and validated against test results and then used to perform parametric studies. • Design rules were assessed for their applicability to S890 UHSS CHS under combined compression and bending. [ABSTRACT FROM AUTHOR]

[Display omitted] • The flow behaviour of different GDEs geometries for PEMWE has been studied. • Square GDE (SGDE) performed better water transfer for the PEMWE test cell. • Flow is directed to the outlet by 38.96% less pressure loss in SGDE geometry. • Water transfer inside the cell may be improved with SGDE for the anode GDE. Polymer Electrolyte Membrane Water Electrolyzers (PEMWEs) can produce green hydrogen with zero emission with renewable energy sources integration. The gas diffusion electrodes (GDEs) are one of the main components of PEMWE. In this study, the flow behavior of GDEs for different patterns like square GDE (SGDE), circle GDE (CGDE), equilateral triangle GDE (ETGDE), and rhombic GDE (RGDE) was investigated numerically and experimentally for different flow rates at 100 mL min−1, 200 mL min−1, and 300 mL min−1. In pressure drop (ΔP) and flow visualization experiments, SGDE showed the best performance. Experimental results were compared with each other by validating them in the numerical analysis of multiphase flow conditions. As a result, at 100 mL min−1 flow rate, the flow is directed to the outlet side with 38.96 % less pressure loss in SGDE geometry. In flow visualization experiments, at 100 mL min−1 flow rate, SGDE geometry fills the cell faster than other GDE geometries by 0.437 sec. The results from the ex-situ ink test performance of the GDEs were confirmed in electrochemical single cell PEMWE tests via Pt coated GDEs. Furthermore, SGDE exhibited superior performance in the in-situ tests. In the numerical calculation results, when 16 % porosity filter paper was examined, it was concluded that the SGDE geometry was 94.8 % rate successfully carried the liquid phase to all geometry. It is supposed that water transfer inside the cell may be improved by using an SGDE for the anode GDE, and the performance of PEMWE could be increased by providing faster delivery of the oxygen gas and excess water to the outside of the cell. [ABSTRACT FROM AUTHOR]

The paper numerically studies the process of pressurized hydrogen release through a hole or a slit into a confined space filled with air. Based on the obtained results, three basic consequences of hydrogen release are demonstrated depending on the initial pressure of hydrogen and the distance to the obstacle: (i) hydrogen ignition before the interaction of the flow with the obstacle, (ii) hydrogen ignition after the flow interaction with the obstacle, (iii) jet flow without ignition. It is shown that ignition limits are wider when hydrogen is released through the slit compared to the case of hydrogen release through a small hole. A similar effect could be achieved by changing the geometry and volume of the vessel from which hydrogen is released. Results of this study can be applicable to the elaboration of hydrogen power engineering systems dedicated either to the combustion initiation or to the suppression of ignition of non-premixed hydrogen-air mixtures. • Self-ignition of hydrogen released into the confined space is studied numerically. • Three basic scenarios of hydrogen release are distinguished and demonstrated. • Mechanism of hydrogen jet ignition due to interaction with obstacle is revealed. • Diagrams of critical conditions for different scenarios are presented. [ABSTRACT FROM AUTHOR]

Energy walls are earth retaining structures equipped with pipe heat exchangers that harvest thermal energy sources from underground. Unlike fully embedded energy geostructures such as energy piles, energy walls interact not only with the ground but also with internal airflows under a wide range of conditions. Yet little is known as to how the internal airflows affect the heat exchange potential and mechanics of energy walls. In this paper, we conduct a systematic investigation into the effects of internal airflows on various aspects of energy wall performance, from the harvestable thermal power to the structural behavior. We construct and validate a numerical model of a full-scale energy wall. We then utilize the model to develop a comprehensive understanding of how internal airflows affect the energy, geotechnical, and structural performance of energy walls under a wide range of site and operational conditions. Results show that an internal airflow not only increases the heat exchange potential of energy walls but also leads to marked variations in the thermally induced axial forces, shear forces, and bending moments in the walls. Our findings consistently indicate that even minimal airflows should be considered in the analysis and design of energy walls. • Internal airflows affect the heat exchange potential and mechanics of energy walls. • Even minimal airflows have remarkable effects on energy wall performance. • Airflow effects should be considered in the analysis and design of energy walls. [ABSTRACT FROM AUTHOR]

Super-hot rock geothermal is an emerging source of renewable and carbon-free energy. This paper is the first attempt to explore fluid and heat flow dynamics in the reservoir-wellbore coupled system, to assess the power generation performance of a super-hot (>450 °C) enhanced geothermal system (EGS). We developed a high-performance code and built a 3-D wellbore-reservoir coupled model based on data from a recently completed deep-drilling project at Larderello, Italy. The general pattern of the super-hot EGS is characterized by a significant temperature plummet (>60 °C), after which the production fluid evolves from steam to a two-phase mixture till the end of the operation period. Reservoir pressure emerges as a key parameter to determine the temperature of the two-phase mixture. By realistically capturing phase transitions driven by coupled thermo-hydraulic processes during operations, our numerical model predicts a lower power generation efficiency compared to previous attempts based on ultra-simplified models. Although finalized at assessing the thermodynamic viability of a specific system, this modeling approach provides general information on fundamental thermo-hydraulic processes in the Earth crust that might be applied for the design of similar EGS projects elsewhere. [ABSTRACT FROM AUTHOR]

Abstract Winter road maintenance is costly but it is necessary in order to keep roads accessible and safe during winter. Current winter road maintenance methods use 600,000 tons of salt annually, in the Nordic countries. The salt ends up in the environment along the roads and results in environmental challenges. Alternative winter maintenance methods that use heat instead of salt are in use today. However, those systems are designed to use high temperature of about 20–35 °C. This paper presents a numerical model for designing low temperature (4–8 °C) hydronic heated pavements (HHP). The model is validated against an experimental setup and different control strategies are evaluated. The validation indicated that the developed model can predict the behavior of the HHP with a root mean square error (RMSE) <1.4 °C for surface temperatures and <0.4 °C for the return fluid. In this paper the model is used with two different control strategies. A basic strategy controlling the system based on air temperature and one strategy based on dew point temperature. With dew point regulation the energy consumption can be reduced by 62%. However, the energy consumption is still in the range of 125–180kWh/m2 for the location of Östersund, Sweden. We found that the HHP system can utilize low temperature sources like waste energy or geothermal energy that is freely available. By using renewable energy for winter road maintenance, the environmental impact from winter road maintenance can be reduced. Highligths • Dewpoint control reduces the energy demand for heated pavements. • Low supply temperatures of 2-8 °C makes it possible to use renewable energy sources. • Presents a 3-D numerical model including the fluid domain for heated pavements. • Snow ploughing strategies affects the energy usage more a low temperature. [ABSTRACT FROM AUTHOR]

Highlights • There has been growing interest in the study of masonry cross vaults. • Cross vaults structural pathologies and repairing interventions are discussed. • The paper analyses the leading numerical strategies adopted for masonries. • This paper describes the main advances in the field of masonry cross vaults. Abstract Masonry cross vaults, which began to be built in Europe in the times of the Roman Empire and reached heights of extraordinary splendor during the Gothic Period, are part of an impressive architectural heritage, which stand in need of evaluation, maintenance and repairs or renovation. Nowadays, the requirements of preservation and conservation of the historical heritage call for a strategy oriented on the description of the structural behaviour from different characteristic perspectives without neglecting the functional, architectonic and structural features. The present paper is intended to discuss the different research approaches adopted by several authors during the past and to show how numerical simulations in conjunction with experimental studies can provide the tools for the quantification of the damages produced by a variety of different critical events. To this scope, this paper includes an extensive and somewhat ambitious review, dealing with a wide variety of aspects, such as: (a) a bibliometric study, (b) classification of the types of cross vaults, (c) structural behavior, (d) types of failures and damage, (e) numerical simulation, (f) experimental testing, (g) monitoring, and (h) retrofitting. The review is expected to be of great interest for architects and engineers working in the field of evaluating and retrofitting the architectural heritage, as well as to those researchers who would find it useful to have at hand in a single document the most important advances made in the field of masonry cross vaults in recent years. [ABSTRACT FROM AUTHOR]

[Display omitted] • Evaporation affects ignition in homogeneous conditions by changing thermal states. • Stratification causes preferential ignition, front propagation and scalar dissipation. • Induction timescale is analyzed by statistics in turbulent environments. • Enhanced turbulence and scalar dissipation cause non-monotonic deflagration speed. • Turbulence affects ignition front by changing spatial gradients of ignition delay. Internal combustion engines are the dominant power sources in transport, accounting for significant amounts of fuel consumption and pollutant emissions. Low-temperature combustion is a promising technology for engine combustion, whose main challenge is the complex control of two-stage auto-ignition that determines the performance of a low-temperature combustion engine. This paper systematically reviews the state-of-the-art advances in auto-ignition modeling which is an essential tool to understand auto-ignition mechanisms and provides valuable guidance for designing more efficient and cleaner engines. This paper focuses on turbulence, evaporation and chemistry effects without the consideration of inter-droplet interactions. Five models with increasing complexity are discussed and compared, including homogeneous models without and with evaporation (models 1 and 2), droplet simulation in static environments (model 3), and direct numerical simulation without and with evaporation (models 4 and 5). Rapid mixing leads to homogeneous conditions in models 1 and 2, in which two-stage auto-ignition is divided into low-temperature induction, low-temperature auto-ignition, high-temperature induction and high-temperature auto-ignition. Model 1 only considers chemical reactions and auto-ignition is determined for a certain thermal state. Droplet evaporation affects the auto-ignition evolution in model 2 through evaporation-induced changes in the thermal state. Compared with homogeneous models, droplet evaporation in model 3 leads to compositional and temperature stratifications which cause three new phenomena: preferential auto-ignition, reaction front propagation and non-zero scalar dissipation rate. Models 4 and 5 introduce turbulent effects on induction timescale and front propagation. Finally, challenges and future directions in auto-ignition modeling are outlined. [ABSTRACT FROM AUTHOR]

Converting waste biomass to fuel and coupling it with solid oxide fuel cell to generate electricity cheaply and efficiently is what researchers are pursuing to achieve carbon neutrality. Therefore, a novel scheme of biosyngas-fueled solid oxide fuel cell power generation integrated with carbon capture is proposed in this paper, fully converting woody biomass into syngas. Based on the mathematical modelling, this system is evaluated by multiple evaluation criterion, including thermodynamic, economic and environmental perspectives. The correctness and accuracy of the proposed model are validated against the published literature. The studies on the key operating parameters show that increasing the gasifying temperature can markedly improve the quality of syngas, while the improvement of steam to biomass ratio is not evident, and the conversion ratio of water gas shift reactor is crucial for carbon capture. Moreover, low current density and high fuel utilization ratio are preferable to the high-efficiency power generation of solid oxide fuel cell. After multi-objective optimization, the CO 2 emission ratio and energy efficiency achieve 0.285 t/MWh (is the lowest among various schemes) and 52%, which proves that the proposed scheme is a highly-efficient and eco-friendly power generation system. [ABSTRACT FROM AUTHOR]

• Numerical modeling to investigate relative density effects on shallow TBM tunneling. • Calibrated NorSand model for sandy soil behavior with different relative densities. • FEM models accurately mirror tunnel behavior from centrifuge tests. • Relative density of sandy soils greatly affects ground response around tunnels. • Felipe P. M. Vitali, on behalf of all co-authors. Tunnel construction in urban areas may result in ground deformations that pose a risk to existing buildings and infrastructure; thus, accurate prediction of these induced ground deformations during the design phase is crucial. The paper focuses on the effects of sandy soil relative density on the ground deformations induced by tunnels excavated with Tunnel Boring Machines (TBMs). The study utilizes the Finite Element Method (FEM) and the NorSand model to simulate the behavior of a sandy ground. The validity of the FEM modeling approach is established by comparing predictions with results from six centrifuge tunnel tests from the literature. The centrifuge tests were performed on sand at different relative densities, tunnel diameters, and tunnel depths. The parameters for the NorSand model were determined based on laboratory tests. Only the state parameter was modified to achieve the desired relative density in the numerical simulations. The effects of relative density observed in centrifuge tests (Franza et al., 2019) have been numerically reproduced with no further adjustments of the model parameters. The rich outputs from the numerical models enabled an in-depth investigation of tunnel behavior, yielding new insights into how tunnels respond under varying relative densities, depths, and diameters. A comprehensive analysis of the induced ground deformations caused by shallow tunnels in sandy ground and the potential to damage buildings is included. [ABSTRACT FROM AUTHOR]

Perfluorocarbon (PFC) droplets represent a novel class of phase-shift contrast agent with promise in applications in biomedical and bioengineering fields. PFC droplets undergo a fast liquid-gas transition upon exposure to acoustic or optical triggering, offering a potential adaptable and versatile tool as contrast agent in diagnostic imaging and localized drug delivery vehicles in therapeutics systems. In this paper, we utilize advanced imaging techniques to investigate ultra-high-speed inertial dynamics and rectified quasi-static (low-speed) diffusion evolution of optically induced PFC droplet vaporization within three different hydrogels, each of different concentrations, examining effects such as droplet size and PFC core on bubble dynamics and material viscoelastic properties. Gelatin hydrogels reveal concentration-dependent impacts on bubble expansion and material elasticity. Embedding PFC droplets in gelatin increases internal pressure, resulting in higher equilibrium radius and continuous bubble growth during quasi-static evolution. Similar trends are observed in fibrin and polyacrylamide matrices, with differences in bubble behavior attributed to matrix properties and droplet presence. Interestingly, droplet size exhibits minimal impact on bubble expansion during inertial dynamics but influences quasi-static evolution, with larger droplets leading to continuous growth beyond 60 s. Furthermore, the core composition of PFC droplets significantly affects bubble behavior, with higher boiling point droplets exhibiting higher maximum expansion and faster quasi-static dissolution rates. Overall, the study sheds light on the intricate interplay between droplet characteristics, matrix properties, and multi-timescale bubble dynamics, offering valuable insights into their behavior within biomimetic hydrogels. [ABSTRACT FROM AUTHOR]

Highlights • The COREDIV code has been used to simulate DEMO inductive discharges with different impurity seeding (Ar, Xe) and mix gasses. • For xenon seeding for case with standard radial diffusion in SOL, such regime of operation seems not to be possible. • For Ar and combined Ar+Xe seeding it is possible to achieve H-mode plasma operation with acceptable level of the power to the target, but is upper limit on Xe concentration. • The influence of the prompt re-deposition model on the DEMO working point is relatively weak. Abstract In this paper numerical simulations with COREDIV code, which self-consistently solves radial transport equations in the core region and 2D multi-fluid transport in the SOL of EU DEMO discharges in full tungsten environment (W divertor and wall) for H-mode scenario has been performed with different impurity seeding. The optimal impurity mix for reactor would require the use of high Z impurity (low dilution, higher P α) in core and low/medium Z impurity radiating in the SOL region. In this paper we focus on investigations how the operational domain of EU DEMO can be influenced by different seeding (Ar, Xe) and mix gasses. In case of Xenon seeding, H-mode operation can NOT be achieved for standard radial diffusion (D SOL = 0.5m2/s) in the SOL. In the simulation, we have considered combined seeding of Ar (good radiator in SOL) and Xe (good radiator in core). In order to find the optimal impurity mix, simulations have been performed in such a way that for a few fixed levels of Xe puff, Ar puff has been increased from zero to the maximum value allowed by the code stability. For combined seeding: xenon + argon working point for EU DEMO can be found. [ABSTRACT FROM AUTHOR]

Precast segmental bridge columns (PSBCs) have significant advantages, including faster construction speed and lower environmental impacts, over cast-in-place bridge columns. Traditional PSBCs usually employ normal-strength steel rebars as longitudinal reinforcement. Hence, it is named the NSR-PSBC herein. In this paper, a novel PSBC, named hybrid-reinforced PSBC (HR-PSBC), is developed. The HR-PSBC utilizes hybrid normal- and high-strength steel rebars to improve the seismic response of PSBCs. The main contributions of this study include: (1) large-scale cyclic tests were conducted to compare the seismic performance of the HR-PSBC with the NSR-PSBC; and (2) a novel and computationally efficient finite element model for the HR-PSBC was developed. The test results demonstrated that the hybrid reinforcement employed in the HR-PSBC was very effective in improving the post-yield stiffness, self-centering capacity, ductility and load-carrying capacity of the bridge column. These test results were further used to verify the accuracy of the proposed finite element model. It was found that the numerical model was able to provide satisfactory predictions of both global and localized responses of the PSBCs. Based on the results presented in this paper, it is concluded that the HR-PSBC can be a promising alternative to traditional NSR-PSBCs and cast-in-place bridge columns, and the proposed numerical modeling method can be a suitable tool for design-oriented studies of the NSR- and HR-PSBCs. [ABSTRACT FROM AUTHOR]

A numerical assessment study of tsunami attack on the rubble mound breakwater of Haydarpasa Port, located at the southern entrance of the Istanbul Bosphorus Strait in the Sea of Marmara, Turkey, is carried out in this study using a Volume-Averaged Reynolds-Averaged Navier-Stokes solver, IHFOAM, developed in OpenFOAM ® environment. The numerical model is calibrated with and validated against the data from solitary wave and tsunami overflow experiments representing tsunami attack. Furthermore, attack of a potential tsunami near Haydarpasa Port is simulated to investigate effects of a more realistic tsunami that cannot be generated in a wave flume with the present state of the art technology. Discussions on practical engineering applications of this type of numerical modeling studies are given focusing on pressure distributions around the crown-wall of the rubble mound breakwater, and the forces acting on the single stone located behind the crown-wall at the rear side of the breakwater. Numerical modeling of stability/failure mechanism of the overall cross-section is studied throughout the paper. The present study shows that hydrodynamics along the wave flume and over the breakwater can be simulated properly for both solitary wave and tsunami overflow experiments. Stability of the overall cross-section can only be simulated qualitatively for solitary wave cases; on the other hand, the effect of the time elapsed during tsunami overflow cannot be reflected in the simulations using the present numerical tool. However, the stability of the overall cross-section under tsunami overflow is assessed by evaluating forces acting on the rear side armor unit supporting the crown-wall of the rubble mound breakwater as a practical engineering application in the present paper. Furthermore, two non-dimensional parameters are derived to discuss the stability of this armor unit; and thus, the stability condition of the overall cross-section. Approximate threshold values for these non-dimensional parameters are presented comparing experimental and numerical results as a starting point for engineers in practice. Finally, investigations on the solitary wave and tsunami overflow experiments/simulations are extended to the potential tsunami simulation in the scope of both representation of a realistic tsunami in a wave flume and stability of the rubble mound breakwater. [ABSTRACT FROM AUTHOR]

This paper considers a simplified single-phase depth-averaged model for simulating rock-ice avalanche movement, which incorporates an energy conservation equation to describe the evolution of mass temperature, accounting for the transition from negative to positive values and vice versa. Additionally, this model introduces a saturation parameter that quantifies the impact of pore water pressure on the normal stress of flow materials. To validate the feasibility of the presented model, two laboratory experiments are simulated. Based on the comparison between numerical results and measured data, this study demonstrates that the presented model captures the transformation of rock-ice avalanches from granular flow to debris flow induced by ice melting during movement and the evolution of associated variables including ice volume fraction and temperature. This study further investigates the impact of factors such as fluid viscosity and melting water on rock-ice avalanche movement through simulation. The findings demonstrate that fluid viscosity has an impact on the morphology of rock-ice avalanches and the rate of ice melting. Consequently, this influence directly affects the movement of rock-ice avalanches. In addition, the cohesive force generated by meltwater impedes the progression of low-speed rock-ice avalanches, particularly those with lower water content. • A depth-averaged single-phase rock-ice avalanche model that considers ice melting and temperature evolution is proposed. • A parameter is introduced to quantify the impact of ice melting on the pore water pressure of flow materials. • Fluid viscosity influences the rate of ice melting, thereby affecting the movement of rock-ice avalanche. • Water cohesive forces hinder the movement of low-speed rock-ice avalanches characterized by lower water content. [ABSTRACT FROM AUTHOR]

The monopile-bucket composite foundation is an innovative offshore wind turbines (OWTs) foundation type for its good bearing properties. This paper establishes the 3D finite element models to explore the lateral bearing behaviors for the composite foundations in sand-overlaying-clay deposits. After model verification, the failure mechanisms of the monopile foundations, single suction bucket and monopile-bucket composite foundations are systematacially analyzed. In addition, a detailed parametric study is undertaken to quantify the effects of potential parameters on the lateral bearing behaviors of composite foundation. Finally, the load sharing ratio between the monopile and suction bucket in composite foundation under lateral loading is investigated. It is found that the composite foundation is superior to that of single pile. Increasing the bucket diameter, bucket length, and overlaying sand layer thickness, the bearing capacity of composite foundation can be enhanced. Among them, the variation of bucket diameter has the most significant effect, while raising the loading point height will weaken the lateral resistance. When the dimensionless pre-vertical load increases from 0 to 0.7, the foundation bearing capacity is improved, and more than 0.7 leads to weakening. • Through numerical simulations, the bearing behaviors for the composite foundation in sand-overlaying-clay deposits under lateral loadings are investigated. • A detailed parametric study is undertaken to quantify the effects of potential parameters on the lateral bearing behaviors for the composite foundations. • The load sharing ratio between the monopile and suction under lateral loading is investigated. [ABSTRACT FROM AUTHOR]

• The structural behavior of S960 hot-rolled UHSS seamless circular hollow section (CHS) beam–columns was studied. • 10 beam–column tests on S960 hot-rolled UHSS seamless CHS were conducted. • FE models were developed and validated against test results and then used to perform parametric studies. • The current design methods were assessed for their applicability to S960 hot-rolled UHSS seamless CHS beam–columns. The rapid development of manufacturing techniques and material science enables advanced hot-rolled ultra-high strength steel (UHSS) with material grades up to S960 to be available recently. The structural performance of S960 hot-rolled UHSS seamless circular hollow section (CHS) beam–columns manufactured through the advanced fabrication approach was experimentally and numerically investigated and reported in this paper. In physical testing, totally ten beam–column specimens were tested, with the complementary material testing and initial global geometric imperfection measurements through the innovative digital image correlation (DIC) method performed. FE modeling was then carried out; FE models of S960 hot-rolled UHSS seamless CHS beam–columns were established and then validated the test observations in terms of the failure loads and the load–mid-height lateral displacement curves. Parametric studies were thereafter performed, with cross-section dimensions, member lengths and loading combinations varying within a certain range, resulting in the additional 300 data to be acquired. Finally, the applicability of existing design methods, as prescribed in the European code, the Australian standard and the American specification, to S960 hot-rolled UHSS seamless CHS beam–columns was evaluated. It can be concluded from the evaluation results that all the three design codes provide accurate and consistent failure load predictions for S960 hot-rolled UHSS seamless CHS beam–columns. [ABSTRACT FROM AUTHOR]

Plowing refers to the phenomenon by which a landslide displaces and pushes the path material forward. Despite its importance in shaping the dynamics of many rapid flow-like loess landslides, the mechanism of plowing is not fully understood. Therefore, this paper presents an improved numerical model based on the material point method (MPM). This model takes into account the interactions between the landslide mass and the path material. The reliability of this model was validated by simulating two granular column collapse experiments involving interaction with an erodible mass. The model was then applied to analyze the plowing dynamics of the Ximiaodian loess landslide in Jingyang County, Shaanxi Province, China. A series of well-designed simulations were conducted to investigate this specific landslide event, contributing to a deeper understanding of the plowing phenomenon in loess landslides. The simulation results show that our model can satisfactorily simulate the plowing process of the Ximiaodian landslide. The plowing process of a rapid-flow loess landslide is proposed to consist of four distinct stages: 1) the collision stage, when the landslide strikes the terrace, resulting in the bending of its strata; 2) the shear failure stage, characterized by significant plastic shear deformation within the bent strata, resulting in the formation of multiple shear failure planes; 3) the steady plowing stage, during which the deformation structure in the affected terrace stabilizes and plowing continues in a steady pattern; and 4) the stopping stage, when the propagation of the disturbed terrace gradually stops. Furthermore, the disturbed terrace zone exhibits three distinct deformation structures. In the rear part, a stable zone develops where the terrace layers are compressed. However, due to the compressive forces exerted by the overlying loess, no significant shear deformation is observed. The middle part is the shear failure zone, characterized by the formation of multiple shear failure planes. The front part is the upheaval zone, where the terrace layers are slightly bent and tilted. • An improved MPM model is proposed to simulate the plowing process of rapid flow-like landslides. • The plowing mechanism of a real loess landslide is analyzed by the MPM model for the first time. • The plowing process of a rapid flow-like loess landslide consists of four stages. • Three distinct deformation structures are formed in the disturbed terrace zone during the plowing process. [ABSTRACT FROM AUTHOR]

The author of the paper presents the practical, environmental and economical results of research studies carried out on a building component used for thermal insulation in horizontal partitions and in for other applications. The said building component is a flexible plate based on recycling materials, which for the case investigated in this paper is Styrofoam regranulate (the said development has been registered as industrial pattern issued for the Silesian University of Technology: Flexible insulation plate No 23621). The scope of the research studies comprised in-situ measurements of temperature and humidity in the layers of the ventilated flat roof insulated with the said plates. For comparison, a part of the roof has been insulated with a standard insulation material, commonly used, such as mineral wool (parameters are similar to the flexible plate made of Styrofoam granulate). In the course of the studies, the parameters of the internal and external environments were recorded (humidity and temperature). Having completed the measurements, numerical analyses were carried out, using the measured parameters of the environment. In the final part of the paper, selected results of the research studies and modeling were presented. The subject involving the application of recycling materials presented in this paper is a part of a larger research cycle carried out by the author. It involves the use of waste materials and their further reapplication in the production of insulation products. [ABSTRACT FROM AUTHOR]

In the present paper, a two dimensional axisymmetric Finite Element Method (FEM) is developed to carry out a thermo-mechanical analysis on a horizontal storage tank intended to storage hot water for a domestic application. The purpose of these numerical simulations is to assess the thermo-mechanical behavior of a horizontal tank with evacuated tube collectors, and consequently to suggest a new design which ensures an optimum mechanical strength according to severe applied operating conditions in terms of temperature and pressure. To achieve this goal, a thermo-mechanical 1-way sequential coupling has been used as a solving method. The physical model suggested in this study and the simulations procedure was described under detailed assumptions. In fact, the main hypotheses in the current formulation were the thermo-elastic behavior of the tank's materials and the steady state assumption analysis. This paper outlines three studies that were performed to extend the lifespan of the horizontal storage tank, through the definition of a suitable material and an optimal design. The main conclusions of the assessment are that the optimal configuration which avoid the appearance of the stress concentration zones is the configuration (c), where Ri = 11 mm and Re = 14 mm, because the stress on the tank's shell was better applied. Moreover, the effect of the material's selection was carried out, and it was found that stainless steel is the optimal material. Last but not least, a set of simulations were conducted to investigate the tank shell thickness on which the thermo-mechanical constraints were applied. The thickness t = 2 mm was presenting an optimal mechanical behavior with regard to the studied operating conditions. [ABSTRACT FROM AUTHOR]

[Display omitted] The high corrosion resistance, low density, and useful biological activity with heat resistance of titanium alloys have made them the most outstanding choice in various industrial applications. However, their poor tribological properties inhibit utilizing them in applications that need abrasive and adhesive wear resistance. Laser cladding is being applied to increase the capabilities of such alloys by allowing the deposition of different hard coating materials. This paper attempts to study the thermal, microstructure, and clad layer geometry evolution during coaxial laser cladding of Ti6Al4V titanium alloy with tungsten carbide + nickel-based alloy preblended powder. Owing to the difficulty in experimentally measuring the thermal and microstructure evolution due to lots of laser processing parameters, a new three-dimensional numerical model based on finite-difference analysis for studying the entire process has been proposed. The behavior of the different thermophysical properties of WC, NiCrBSiC, and Ti6Al4V materials, as well as the phase transition based on latent heat and fluid dynamics considering materials velocity, viscosity, and buoyancy force, during melting and resolidification processes, were considered to improve and ensure the accuracy of the numerical model. The proposed model could be applied to accurately estimate the temperature history and the deposited clad layer morphology and geometry. The cooling rate and thermal gradient were investigated to predict the solidification rate and microstructure by using different laser cladding parameters. It was confirmed that the laser power has a substantial impact on the peak temperature in the melt-pool, while the laser scanning speed has a significant effect on the heating and cooling rates. In conclusion, the process parameters have to be carefully chosen to certify a good quality clad layer with the preservation of the WC particles. [ABSTRACT FROM AUTHOR]

The direct application of glycerol in solid oxide fuel cell (SOFC) for power generation has been demonstrated experimentally but the detailed mechanisms are not well understood due to the lack of comprehensive modeling study. In this paper, a numerical model is developed to study the glycerol-fueled SOFC. After model validation, the simulated SOFC demonstrates a performance of 7827 A m−2 at 0.6 V, with a glycerol conversion rate of 49% at 1073 K. Then, parametric analyses are conducted to understand the effects of operation conditions on cell performance. It is found that the SOFC performance increases with decreasing operating voltage or increasing inlet temperature. However, increasing either the fuel flow rate or steam to glycerol ratio could decrease the cell performance. It is also interesting to find out that the contribution of H 2 and CO to the total current density is significantly different under various operating conditions, even sometimes CO dominates while H 2 plays a negative role. This is different from our conventional understanding that usually H 2 contributes more significantly to current generation. In addition, cooling measures are needed to ensure the long-term stability of the cell when operating at a high current density. • SOFC with Glycerol Steam Reforming is modelled. • The contributions of H 2 and CO on current generation are studied. • CO may play a dominating role in current generation. • The temperature field of glycerol fueled SOFC is investigated. [ABSTRACT FROM AUTHOR]

The paper presents the mathematical model of the heat transfer processes for a single screw ash cooler (SSAC) working with a circulating fluidized bed (CFB) boiler. The validation of the model is based on experimental measurements made on a 230 MWe power unit. The analysis of measurement data from two bottom ash coolers showed that the correct prediction of the outlet temperatures of ash and cooling water requires the determination of their individual ash filling characteristics (i.e. coolers). The numerical results confirm that the mixing model proposed by Schlünder correctly predicts the heat transfer coefficient for ash. The described mathematical model can monitor the operating conditions of the single screw ash cooler. It enables the determination of the optimal volumetric flow rates of the cooling water in order to get its highest possible outlet temperature, and then for this water to be used, e.g. for sanitary purposes. [Display omitted] • Mathematical model of ash cooler is successfully verified with experimental data. • Schlünder model of particle mixing is used to calculate heat transfer coefficient. • Characteristic of filling ash cooler with ash is a key part of mathematical model. [ABSTRACT FROM AUTHOR]

• First-time measurement of scroll vortex intake flow field using non-intrusive LDA. • 3D CFD model results compare well with experimental measurements. • Scroll chamber flow resembles a free vortex with constant circulation. • Bellmouth outlet flow possesses smaller circulation than the scroll chamber flow. • Vertical velocity in the dropshaft is approximately constant across flow thickness. Scroll vortex intakes are hydraulic structures commonly used in water supply, drainage and sewerage systems. Water flows into the intake via an eccentric approach channel and a vortex chamber imparts swirl to the flow, leading to a stable air core vortex along the dropshaft. Although much effort has been devoted to investigate the scroll vortex flow, yet the understanding on its hydraulic characteristics is still far from complete due to a lack of detailed velocity field measurements. This paper presents the first comprehensive measurement of the three-dimensional (3D) flow field of a scroll vortex intake using non-intrusive Laser Doppler Anemometry (LDA). A validated 3D Computational Fluid Dynamics (CFD) model with the Volume-Of-Fluid (VOF) method is developed for interpreting the measurement. It is found that the vortex flow in the scroll chamber resembles a free vortex and the circulation is approximately equal to that at the chamber inlet, with a thin bottom boundary layer. The vortex flow at the bellmouth outlet possesses a circulation constant smaller than that in the chamber, and its vertical velocity component is approximately constant across the flow thickness. [ABSTRACT FROM AUTHOR]

Multiwall plates consist of parallel thin-walled plates connected by a given number of vertical ribs to yield a light and yet a high strength structure. Unlike composite and sandwich plates, the multiwall plate does not have cross-section material continuity and therefore cannot be analyzed in terms of stress distribution in a simple way. The first order shear deformation theory (FSDT) model is used to obtain a homogeneous plate. Innovative analytic and finite element models were developed to obtain the elastic equivalent constants of the plate. A good matching was obtained between the analytic model results and the numerical ones. It turned out that the analytical approach cannot yield all the elastic equivalent constants, therefore an experimental approach was developed and implemented to obtain all the equivalent elastic constants of a typical multiwall plate. Those results were in good matching with the numerical finite element ones. The structural response to loading for the orthotropic equivalent plate can be easily calculated either analytically, numerically or experimentally. • A homogenization of multiwall plates yielding an orthotropic solid plate with equivalent properties was validated numerically, analytically and experimentally. The authors believe that this was done for the first time for such type of plates. • The output of the present paper is that calculating by FEA the deflection of a rectangular homogenized plate reduces drastically the computation time as compared with the full original plate. This should be hold as the second highlight. • It turned out that a multiwall plate structure has a relatively low transverse shear rigidity in y direction. Therefore, shear deformations must be considered in the design process. Also, the plate's twist rigidity is reduced due to this low rigidity. This conclusion should be considered as the third highlight of the present paper. • It seems than in a multiwall rectangular plate, the Poisson's effect induces a stress in the ribs under y direction tension and bending. This is different from a solid plate, where Poisson's strains are stress less. This interesting conclusion would be the 4th highlight. [ABSTRACT FROM AUTHOR]

• We propose a fast error estimation method for LRBF for the first time. • Based on the error estimation method, we propose an adaptive shape parameter selection strategy for LRBF for the first time, and give a complete process. • A particle swarm optimization algorithm is used to realize the complete process proposed above, and the feasibility of this method is verified by using test functions and multi type boundary problems. Radial basis function (RBF) is a basis function suitable for scattered data interpolation and high dimensional function interpolation, wherein the independent shape parameters have a direct impact on the accuracy of calculation results. Research in this field is mostly concerned with the shape parameter selection strategy based on the premise of global distribution or block regional distribution. In this paper, a shape parameter selection strategy is proposed, which is used for the local RBF collocation method (LRBF) for solving partial differential equations. It overcomes many limitations of the traditional methods applied to LRBF. In this strategy, a set of twin matrices similar to the interpolation matrix are constructed to evaluate the error of the model. In addition, the penalty term contained in the twin matrix is used to relax the influence of the far end region on the target node. Since the objective problem is nonlinear, a particle swarm optimization algorithm (PSO) is employed to minimize the training objective and adjust the shape parameters of the basis function at each iteration. Extensive numerical results showed the effectiveness of the error estimation strategy, by providing a good shape parameter and better solution accuracy. At the end of the paper, the generality of the shape parameter optimization framework based on this strategy is discussed through three examples. [ABSTRACT FROM AUTHOR]

[Display omitted] • Measurements at the cutting area are carried out during drilling tests on tubes. • A multi-scale cutting model is developed for drilling of Ti-6Al-4V. • The numerical thermal loading is validated from experimental data. • The numerical thermal fields are validated by experiments after several revolutions. • The model can evaluate the percentage of heat that spreads within the workpiece. The present paper investigates the thermo-mechanical loading involved in hole drilling of Ti-6Al-4V. Indeed, the heat and strains developed in a very restricted area at the tool vicinity are responsible for various undesired side effects among which: tool damage, residual stresses, poor surface roughness, and metallurgical alterations. The confined nature of the drilling process prevents from any experimental access to some governing physical data such as local strain fields and local energies. Therefore a mixed numerical-experimental approach is herein proposed in order to provide local in-sight to essential tool-related thermal and mechanical sources. It relies on strain and temperature measurements at various locations of the cutting edge that are used to validate a multi-scale numerical model. This latter is then used to assess the energy budget involved in the material removal. The presented results prove the ability of such technique in obtaining valuable information on the in-process generated heat and the way it spreads within the workpiece and beyond. Results also show the spatial heterogeneity of the cutting phenomenon along the cutting edge and highlight the complexity of defining optimal cutting parameters and optimal tool design. [ABSTRACT FROM AUTHOR]

Due to the increasing trend in consumer habits to use healthy food products with low fat content, reduction of oil uptake during different frying processes is necessary. Recent studies have clearly revealed that microstructural changes occurred during frying operations significantly impact oil uptake. These variations are assessed for better comprehension of the mechanisms involved in oil absorption of fried products to minimize oil uptake without sacrificing organoleptic and textural properties of the foods. Different strategies such as state-of-the-art computational simulations based on numerical analysis of simultaneous momentum, heat and mass transfer modeling during frying have been attempted by several researchers to better control the process. This review paper presents a comprehensive and up-to-date review of microstructure variations covering all existing methods of frying operations comprising deep-fat frying, vacuum frying, hot-air frying, non-fat frying and microwave frying together with post-frying treatments and process modeling of frying. Oil uptake can be controlled during frying by proper process design regarding different products and frying operations. Textural and organoleptic characteristics of fried foods are affected by applying various frying processes. Microstructural changes and post-frying treatments influence oil uptake during frying. In addition, suitable design and optimization of frying using process modeling is important to produce fried food products with high quality. • Microstructural changes during frying of foods greatly affect magnitude of oil uptake. • Different frying operations affect textural and organoleptic characteristics of foods. • Hot-air and non-fat frying strategies can significantly lower oil content of fried foods. • Numerical simulations of frying help control oil absorption during the process. • A healthier low-fat fried product is achievable by suitable product and process design. [ABSTRACT FROM AUTHOR]