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Micro elastofluidics is a transformative branch of microfluidics, leveraging the fluid–structure interaction (FSI) at the microscale to enhance the functionality and efficiency of various microdevices. This review paper elucidates the critical role of advanced computational FSI methods in the field of micro elastofluidics. By focusing on the interplay between fluid mechanics and structural responses, these computational methods facilitate the intricate design and optimisation of microdevices such as microvalves, micropumps, and micromixers, which rely on the precise control of fluidic and structural dynamics. In addition, these computational tools extend to the development of biomedical devices, enabling precise particle manipulation and enhancing therapeutic outcomes in cardiovascular applications. Furthermore, this paper addresses the current challenges in computational FSI and highlights the necessity for further development of tools to tackle complex, time-dependent models under microfluidic environments and varying conditions. Our review highlights the expanding potential of FSI in micro elastofluidics, offering a roadmap for future research and development in this promising area. [ABSTRACT FROM AUTHOR]

In recent years, the immense potential for MEMS devices in the biomedical industry has been understood. It has been determined that, among their many plausible functions, their use may also extend to single human red blood cell diagnostics, whereby biomarkers of quantifiable magnitudes may be detected. Without a doubt, the mechanical and thermal specifications by which potential devices must be able to function are very strict. Among them is the ability to operate while fully submerged in aqueous solutions. In this work, six devices were modelled numerically in deionised (DI) water and 0.9 wt% NaCl solution, the results of which were validated experimentally. The mechanical performance of the different devices when fully submerged in 0.9 wt% NaCl solution is hereby discussed. With the exception of one, all the devices in their current configuration are confirmed to be suitable candidates for biomedical applications. [ABSTRACT FROM AUTHOR]

Recently, the thought of nanotechnology has endowed mankind to create materials of nanometer magnitudes. Nanoparticles or nanomaterials have diverse optical, chemical, thermal and physical possessions from their pre-supremacy corresponding item. Hence, this paper comprises the features of a Casson–Williamson flow field with nanoparticles. Here, we explored the impact of rate slip precondition on the mechanics of heat and mass transport over a stretched sheet with viscous dissipation, and heat generation in an exceedingly porous medium. The influence of Soret–Dufour, magneto-hydrodynamics (MHD) and thermal radiation is presumed. All chemical science specifications of nanofluid are measured as constant. As a result of motion of nanofluid particles, the fluid concentration is inspected underneath chemical implications. A collection of coupled partial differential frameworks is accustomed mathematically to formulate the physical model. The scheme for numerical study named Runge–Kutta approach along with shooting technique is implied to solve the obtained equations. The numerical procedure is then displayed pictorially, where fluid velocity, temperature and concentration against various pertinent parameters are examined. The velocity of the nanofluid encompasses a quicker rate within the deficiency of a magnetic factor; however, the velocity field possesses a reverse trend for Casson factor. The higher Eckert number intensifies the temperature of Casson fluid. Furthermore, the Casson parameter and the velocity slip parameter reduce the drag force and local Nusselt number. [ABSTRACT FROM AUTHOR]

Vortex-Induced Vibration (VIV) is a complex fluid–structure interaction in offshore structures. Traditionally, this phenomenon is considered periodic; however, many of its signals show chaotic behavior. The basic model already employed by other researchers is a rigid circular cylinder with linear springs and dampers. In this work, nonlinear snapping support is used to model nonlinearity in the system. To numerically simulate the flow, Reynolds-Averaged Navier–Stokes (RANS) equations for two-dimensional incompressible unsteady flows are applied. The degree of nonlinearity of the system can be changed by manipulating γ , which is one of the geometric properties of the spring and takes values between 0 and 1. The 0–1 test, Poincaré section, and Fast Fourier Transform are used to analyze the cylinder and lift force behavior. Also, the Hilbert transform is applied to the signals, and the phase shift between displacement and lift force is obtained. The results show that the system behavior consists of branches: branch I and branch II. The large amplitudes occur in branch II. It is found that chaos emerges at the beginning of branch II, regardless of the value of γ. By raising the γ value, the span of branch II becomes more expansive, and its first point is placed at lower reduced velocities. Also, the wake dynamics becomes more regular at the end of branch I and more irregular at the beginning of branch II with the increase in γ. When the cylinder displacement signal is chaotic, the lift force behavior is also chaotic, but not vice versa. [ABSTRACT FROM AUTHOR]

Wet assembly is the most common method of joining parts in the aircraft industry. In this case, a layer of liquid sealant is applied to the contact surface of one of the parts, after which the structure is bolted. Despite the practical importance of this issue, until now there has been no mathematical model or software tool that would allow simulating the wet assembly process. This study is devoted to modeling the wet assembly process of large-scale aircraft structures, taking into account the flow of sealant applied between the joined parts. The original mathematical model includes a full two-way interaction of deformable parts and a viscous liquid sealant. Such effects as contact interaction of parts, the presence of the free surface of sealant layer, the sealant curing, deformation and loosening of fasteners are taken into account. The developed mathematical model is applied to the simulation of the assembly process of wing to fuselage upper joint. A special full-scale model has been developed in order to reproduce the effects observed in practical assembly. The numerous numerical experiments demonstrate these effects and illustrate how different parameters of the process affect both intermediate and final results of the assembly. The performed investigation shows how mathematical modeling can contribute to the improvement of existing and development of new technologies on the assembly lines of aircraft manufacturing companies, where any experiments are extremely expensive or simply impossible. [ABSTRACT FROM AUTHOR]

In this study, the growth and rupture of plaque were investigated to predict the development of carotid atherosclerosis and plaque. Realistic 3D models of multi-component plaque and carotid artery were established in healthy, mild, moderate, and severe stenosis. Fluid–structure interaction (FSI) simulations were performed on these models, and the wall shear stress (WSS), time-averaged wall shear stress (TAWSS), oscillatory shear index (OSI), relative residence time (RRT), and wall tensile stress (WTS) in a natural cardiac cycle were analyzed to assess the epidermal rupture, growth tendency, and internal rupture of plaques in a natural state. Results show that in severe stenosis, the WSS at the stenosis sites exceeds the threshold of rupture during almost the entire cardiac cycle, thus causing an epidermal injury, bringing about plaque detachment and thrombosis. TAWSS decreased and OSI and RRT increased in the bifurcation region and the downstream region of the plaque. The deposition is more likely to occur in these regions. A higher degree of stenosis will increase the OSI and RRT in the downstream region of the plaque, leading to continuous deterioration of the plaque, while the degree of stenosis has little effect on the upstream region of the plaque. The fibrous cap is the starting point for rupture within the plaque, and calcification increases the stress on the fibrous cap, thereby increasing the risk of rupture. [ABSTRACT FROM AUTHOR]

Flexible psammophytes play an important role in controlling soil wind erosion and desertification, owing to their characteristics. Although flexibility of psammophytes has been considered in previous studies, the interaction between flexible psammophytes and the surrounding airflow field still remained unclear. In this study, we used the Young's modulus to describe plant flexibility and conducted a 3D computational fluid dynamics simulation using a standard k-e model and a fluid-structure interaction model. Taking Caragana korshinskii (Caragana), a typical psammophyte, as the research object, we constructed 3D geometric models with different diameters to simulate the airflow field around the flexible psammophytes. By comparing with the simulation results of rigid plants and simulation results of flexible plants at different wind speeds, we could verify the rationality of the simulation method. Based on the simulation results, the maximum swing amplitude of the model and the Young's modulus were found to have a negative correlation, presenting an exponential functional relationship with good fitting. The relationship between the actual Young's modulus of the plant branches and that of different diameter models in the numerical simulation was also established. This study is expected to improve our basic understanding of the interaction between flexible psammophytes and the surrounding airflow field, and provide some qualitative reference for the numerical simulation of the airflow field around flexible psammophytes. [ABSTRACT FROM AUTHOR]

Low permeability oil reservoir resources are rich and their efficient development is considered an important way to solve energy security issues. However, the development process of low permeability oil reservoirs is faced with the challenges of insufficient natural energy and rapid production decline. The high-pressure water injection technology is a method that relies on high-pressure and large-volume to inject fluid into the reservoir to replenish energy. It is considered as an important technical means to quickly replenish formation energy. This study focuses on the injection capacity for the high-pressure water injection technology of low permeability oil reservoir. Firstly, the fluid-structure interaction mathematical model for two-phase fluid flow was established. The solution of the mathematical model was then obtained by coupling the phase transport in porous media module and Darcy's law module on the COMSOL numerical simulation platform. The numerical model established in this study was verified through the Buckley-Leverett model. The study on the injection capacity of high-pressure water injection technology was conducted using the geological background and reservoir physical properties of Binnan Oilfield (Shengli, China). The results show that the production pressure difference is the key factor in determining the injection capacity. When the production pressure difference increases from 5 MPa to 30 MPa, the cumulative injection volume increases by 8.1 times. In addition, sensitivity analysis shows that the injection capacity is significantly influenced by the properties of the reformation area. The effect of these parameters from high to low is as follows: stress sensitivity factor, permeability, rock compressibility, and porosity. Compared to the reformation area, the influence of the physical parameters of the matrix area on the injection capacity is negligible. Therefore, effective reservoir reformation is essential for enhancing the injection capacity. This research provides a theoretical basis for the design and optimization of the high-pressure water injection technology schemes for low permeability oil reservoir. [ABSTRACT FROM AUTHOR]

In this paper, a mathematical model of fluid flows in a convective thermal system is developed, and a five-dimensional dynamical system is developed for the investigation of the convective fluid dynamics. The analytical solutions of periodic motions to chaos of the convective fluid flows are developed for steady-state vortex flows, and the corresponding stability and bifurcations of periodic motions in the five-dimensional dynamical system are studied. The harmonic frequency-amplitude characteristics for periodic flows are obtained, which provide energy distribution in the parameter space. Analytical homoclinic orbits for the convective fluid flow systems are developed for the asymptotic convection through the infinite-many homoclinic orbits in the five-dimensional dynamical system. The dynamics of fluid flows in the convective thermal systems are revealed, and one can use such methodology to predict atmospheric and oceanic phenomena through thermal convections. [ABSTRACT FROM AUTHOR]

This study demonstrates the effectiveness of Proper Orthogonal Decomposition (POD) as a method for analyzing flow structures and as a data reduction tool for both numerical simulations and experimental techniques. The reduced data can be integrated to data driven inference of partial differential equations which can lead to reduced order modeling. By focusing on the flow around a cylinder, we show that POD efficiently identifies the most energetic modes, allowing for the flow's reconstruction with a limited dataset. Our findings indicate that the first 10 POD modes appear in pairs with similar spatial patterns, frequency spectra, and energy contributions. These modes encapsulate nearly 92% of the total energy, highlighting the method's precision in capturing essential dynamics. Specifically, modes 1 and 2 correspond to streamwise vortex shedding, while modes 3 and 4 relate to the lateral flow motion. The reconstructed flow, based on these dominant modes, closely matches numerical analysis results, validating POD's utility in developing reduced order models and enhancing our understanding of fluid-structure interactions. [ABSTRACT FROM AUTHOR]

Load modeling in nonlinear statics, particularly incorporating large deformations differs significantly from the treatment in linear analysis. As in structural dynamics masses in a gravity field generate the loading, their location, and their modifications within the deformation process must be considered in a nonlinear simulation. A specific view besides loading by masses is on gas and fluid interaction with structures. In addition, load control using specifically designed algorithms is evaluated with respect to realistic applications. Within the load modeling an unavoidable, however side aspect, is the general discussion about the so‐called follower forces and non‐conservative loading. As an example of real‐world applications, the specifics of inflated rubber dams are presented. [ABSTRACT FROM AUTHOR]

This work investigates the free vibrations of innovative thermally loaded nanoplates constructed by integrating magneto-electro-elastic (MEE) layers with functionally-graded graphene platelet-reinforced composite cores (FG-GPLRC) and accounting for viscous fluid interactions. An advanced multiphysics model is developed using the Navier–Stokes equations to capture fluid structure coupling effects, Halpin–Tsai, and the rule of mixtures micromechanics to predict the non-uniform effective properties, third-order shear deformation plates theory (TSDPT) to incorporate thickness stretching, and the nonlocal strain gradient theory (NSGT) to characterize size dependencies. The Galerkin technique is used to solve the governing equations, which are derived from the Hamilton’s principle. Parametric analyses quantify the influences of fluid depth, temperature fluctuations, temperature profiles, nonlocal and strain gradient parameters, electric and magnetic potentials, graphene distribution patterns, graphene weight fractions, and boundary conditions on the vibration response. The outcomes of this study provide design guidelines and predictive tools enabling active vibration control systems for next-generation thermally-loaded nanocomposite structures with widespread applications from aerospace vehicles to nanoelectronics. [ABSTRACT FROM AUTHOR]

A cell's mechanical environment regulates biological activities. Several studies have investigated the response of healthy epithelial mammary (MCF10A) and breast cancer (MCF7) cells to vascular and interstitial fluid motion-induced hydrodynamic forces. The mechanical stiffness of healthy and breast cancer cells differ significantly, which can influence the transduction of forces regulating the cell's invasive behaviour. This aspect has not been well explored in the literature. The present work investigates the mechanical response of MCF10A and MCF7 cells to tissue-level interstitial fluid flow. A two-dimensional fluid flow–cell interaction model is developed based on the actual shapes of the cells, acquired from experimental fluorescent images. The material properties of the cell compartments (cytoplasm and nucleus) were assigned in the model based on the literature. The outcomes indicate that healthy MCF10A cells experience higher von Mises and shear stresses than the MCF7 cells. In addition, the MCF7 cell experiences higher strain and displacements than its healthy counterpart. Thus, the different mechano-responsiveness of MCF10A and MCF7 cells could be responsible for regulating the invasive potential of the cells. This work enhances our understanding of mechanotransduction activities involved in cancer malignancy which can further help in cancer diagnosis based on cell mechanotype. [ABSTRACT FROM AUTHOR]

Increasing population around the globe due to promotion of industries has created severe problems for human beings like shortage of existing fossil fuels, energy crisis, climate change which are major hurdles for human survival on the planet. To solve all these problems, researchers recommended two appropriate solutions, one of them is to promote thermal energy which is environmentally friendly source of energy and other solution is promotion of ferro-fluid usage as an effective medium for transmission of heat. In recent study, we considered the impacts of thermal energy along with magnetic effects and compute its results. This work is done by using appropriate similarity variables to obtain the system of nonlinear ordinary differential equations (ODEs) from set of partial differential equations (PDEs). We solved the resultant ODEs numerically by means of a famous numerical method termed as bvp4c. Here, effects of Weissenberg parameter, power law index, Curie temperature and radiation parameter are determined for velocity and temperature profiles. Furthermore, graphical representations of velocity as well as thermal gradients are computed. The effects of various parameters on Nusselt number are deliberated and expressed in tabular form. Velocity of magnetized cross ferro-fluid dwindles for β and n. Moreover, it is detected that temperature of ferro-fluid deteriorates for Pr and ε. [ABSTRACT FROM AUTHOR]

Hollow yttrium-stabilized zirconia (YSZ) particles, which are often used to prepare high porosity coatings in industry, hit substrate at a fully molten state or semi-molten state due to the high temperature gradient of particles caused by the low thermal conductivity. Considering the hollow solid core large deformation and liquid solidification during the deposition of semi-molten hollow particles (SMHPs), a fluid-structure interaction model described by the coupled Eulerian and Lagrangian (CEL) method, is developed and validated to investigate the spreading results in thermal spraying. The empirical formula of dynamic viscosity based on the ABAQUS CEL method is proposed and verified for simulation of the liquid YSZ spreading and solidification. The compression ratio and plastic dissipation are calculated to reveal flattening and buckling phenomena of hollow solid core with different initial velocities and hollow radius. Moreover, a double-SMHP impact model is established to simulate the interaction of particle-particle-substrate, and the effect of flattening, buckling and structural self-contact on porosity is analyzed. Numerical simulation results show that hollow solid core large deformation induces instability accompanied by flattening, buckling or structural self-contact, which results in the reduction of layer porosity. [ABSTRACT FROM AUTHOR]

AbstractIn the present investigation, a numerical investigation of the flow and heat transfer characteristics inside an L-shaped enclosure with a flexible fin and an elastic wall has been carried out using the finite element method. The Fluid-Structure Interaction model is used to capture the interaction between the fluid and the solid structure. The free end of the flexible fin is exposed to sinusoidal vertical force and the upper wall of the enclosure is considered to be elastic and a sinusoidal force is applied on this elastic wall. The obtained results showed that the fluid flow through the enclosure is entirely influenced by the periodic oscillation of the flexible fin and elastic wall. Besides, the Nusselt number over the horizontal and vertical hot walls of the L-shaped enclosure is strongly affected by the amplitude and frequency of the applied sinusoidal forces on the flexible fin and elastic wall. The heat transfer over the vertical hot wall is enhanced considerably with an increase in the amplitude and frequency of the applied sinusoidal forces. Moreover, the Nusselt number over the hot vertical wall is increased with the decrease of the elastic modulus value of the elastic wall. The results also show that the combination of the flexible fin and elastic wall has contributed to the extra enhancement of the Nusselt number over the hot vertical wall of the L-shaped enclosure. [ABSTRACT FROM AUTHOR]

We study an elastic particle translating axially along the centre-line of a rigid cylindrical tube filled with a Newtonian viscous fluid. The flow is pressure-driven and an axial body force is applied to the particle. We consider the regime in which the ratio of typical viscous fluid stress to elastic stiffness is small, leading to small elastic strains in the particle. In this case, there is a one-way decoupling of the fluid–structure interaction problem. The leading-order fluid problem is shown to be pressure-driven Stokes flow past a rigid sphere, and is solved using the semi-analytical method of reflections. The traction exerted by the fluid on the particle can be computed and used to formulate a pure solid-mechanics problem for the deformation of the particle, which can be solved analytically. This framework is used to investigate the role of the background flow, an axial body force and the tube wall on the particle's leading-order translational velocity, resulting deformation and induced solid stress. By considering the first-order fluid problem the next-order correction to the translational velocity of the particle is shown to be zero. Depending on the magnitude of the ratio of applied body force to viscous forces, the particle can either have a bullet-like shape, an anti-bullet shape, or retain its original spherical shape. A non-linear arbitrary Lagrangian-Eulerian finite element implementation is used, in conjunction with various existing results from the literature, to validate the method of reflections solutions and interrogate their range of validity. [ABSTRACT FROM AUTHOR]

The present study is able to calculate the effect of tumor presence on the air velocity and relative pressure in the upper respiratory system as in vitro, using fluid-structure interaction method. Three exhaled airflows of 15 L/min, 26 L/min, and 30 L/min were considered to simulate airflow. In this regard, the velocity reaches its maximum in the larynx and oropharynx. The maximum velocities at 15 l/min, 26 l/min, and 30 l/min flow rates are 6.26 m/s, 10.58 m/s, and 12.14 m/s, respectively, which occur in the larynx. The highest relative pressure was experienced in the trachea. So that the maximum relative pressure in the flow rates of 15 l/min, 26 l/min, and 30 l/min was equal to 19.6 Pa, 51.1 Pa, and 65.8 Pa, respectively. Then, by doubling the flow rate, the maximum relative pressure reached more than tripled. The numerical models presented for the respiratory system can be useful for better treatment attitudes. [ABSTRACT FROM AUTHOR]

The vibro-acoustic responses of coupled pump-jet-submarine systems excited by fluid excitations on the wall of the duct are numerically investigated. The unsteady excitations are calculated by computational fluid dynamics and the vibration responses for different excitations on the inner and outer walls are contrastively analyzed through establishing a finite element model of the coupled system. Meanwhile, the effect of fluid–structure interaction and the excitation loading methods for the inner flow of duct are considered. The sound radiation characteristics for different excitation sources are predicted through using a boundary element model. The results show that the excitation force spectra of the inner wall have a remarkable discrete peak at blade passing frequency and its multiple, while the excitation force spectra of the outer wall show a broadband characteristic and discrete components appear at blade passing frequency. The modes of hull both dominate the vibro-acoustic responses of the coupled system for different excitation sources of the duct. The transmitted energy for inner excitation forces is significantly greater than that of outer excitation forces, but the sound radiation efficiency is relatively close. The excitations of the duct can transfer to the thrust bearing through stators as well as the hull and cause a coupled vibration between the duct–stator–hull and the shafting system. Besides, the method for applying distributed forces on the inner wall is more reliable. [ABSTRACT FROM AUTHOR]

Most models employed for fluid forces in drill-string dynamics are of reduced order. The simplified nature of these models often fails to describe the complex behavior of the fluid force, in particular, when the drill-string movement is non-trivial or even when non-Newtonian behavior is predominant. In this work, the fluid forces are estimated by modeling the dynamic of the drilling fluid for both Newtonian and non-Newtonian fluids, and compared with reduced-order models. To achieve it, the lattice-Boltzmann method is implemented to solve the fluid model, while prescribed movements are set for the tool-joint. With the obtained fields, the forces are calculated and compared with recurrent models. Finally, it is observed that some models are capable of describing the interaction as long as the dynamic of the tool-joint is simple. In the presence of other trajectories--e.g., bouncing and chaotic--the models fail to describe the details of the dynamic. [ABSTRACT FROM AUTHOR]

Surface gravity wave interaction with a novel composite pile-rock breakwater having a stack of porous plates fixed on its top is investigated in the present study. A numerical code based on the dual boundary element method (DBEM) is developed to understand the wave scattering and force coefficients within the framework of linearized potential flow theory. Out of the four different proposed configurations (pile-rock alone, vertical, horizontal, and H-shaped porous plate assembly with pile-rock), it is found that novel H-shaped porous plates with submerged pile-rock are effective in attenuating the wave energy. The parametric study for the H-shaped configuration with several key aspects like permeable plate porosity, horizontal plate's submergence depth, pile-rock relative height, and width of the pile-rock barriers are investigated. It is appropriate to use plate porosity in the range of 10-20% to secure wave transmission of less than 0.5 for a wide range of incident wave periods. By changing the relative submergence of the horizontal porous plate from (h2/h = 0.375-0.125), it is possible to reduce the wave transmission by about 10% but at the expense of increasing the vertical wave force by almost 50-75%. Increasing the pile-rock height (h1/h from 0.75 to 0.25) helps to reduce the wave transmission but significantly increases the horizontal wave force and moment on the perforated H-shaped barrier. The results of the parametric study can be used for optimizing the dimensions of the pile-rock cum porous plate wave barrier for a wide range of field conditions. [ABSTRACT FROM AUTHOR]

A two-dimensional model to estimate the hydrodynamic response of hinged multiple floating body systems in the time domain is established based on the Kane method. The reduced Kane equations applicable to the dynamic response of multi-floating body system with hinges are first deduced. The issue of hinge constraint in the system is addressed by defining the corresponding generalized speeds as zeros, while the wave actions are considered based on the potential flow theory. Then the corresponding calculation program is developed prior to undertaking the model test. Verification of the Kane-based model and the veracity of the program developed is performed through a series of contrastive analyses on a hinged floating bridge in various cases including regular waves, moving loads, and their combinations. The predictions obtained by the proposed model show satisfactory agreements with the model test measurements. The related results indicate that the motion responses of the first pontoon are greatest in a hinged floating bridge, and its motion amplitudes descend nonlinearly with the increment of wave frequency. The time-history motion responses of hinged multi-floating bodies in the middle present saddle shapes with some fluctuations as a whole under the combined effect of wave and moving loads. The Kane-based model is convenient to analyze the dynamic characteristics of a hinged multi-floating body system in regular waves, and it could be further extended to consider the effects of irregular waves, inhomogeneous sea conditions, as well as the nonlinear connections on the system. [ABSTRACT FROM AUTHOR]

This paper presents a solution verification and validation study for an overset mesh based numerical wave tank in OPENFOAM, which considers the coupling between a free-surface hydrodynamic flow model, a rigid body motion model, and an overset mesh. The coupling between the rigid body motion solver and the free-surface flow solver was achieved in a segregated manner. Free decay of roll motion of a barge was modeled using the numerical wave tank, and the damping coefficient was selected as the target quantity for solution verification. The least-square based solution verification procedure was adopted, where one of the four types of error estimators was fit to the data in the least-square sense. Both structured and unstructured mesh were tested, and their effects on the convergence order, numerical uncertainty, and error were carefully investigated. From the numerical tests, it is found that the numerical wave tank exhibits a very good convergence property for the floating body problems with structured mesh, i.e., nearly second order in space and first order in time. However, when switching the body-fitted mesh to unstructured mesh, the grid convergence is reduced to first order. Unstructured mesh does not significantly affect the convergence order in time domain, but results in a larger uncertainty due to data scattering. [ABSTRACT FROM AUTHOR]

Thin porous plates serve as an effective model for the construction of breakwater. Thus, the problem involving oblique wave interaction with a tunnel in the presence of a submerged horizontal porous plate over a trench-type bottom is investigated. In this article, for the mathematical formulation of the physical model, water wave potentials are defined using Havelock's expansions and flow past over porous structure is modeled based on Darcy's law. The advantage of the trench type of bottom and horizontal plate is studied through the numerical results of forces on the tunnel. The study reveals that more energy loss and less force on the tunnel are obtained if the porous effect parameter of the plate or the length of the plate is increased up to a moderated value of these parameters. Compared to the case without porous plate and trench-type bottom topography, there are significant changes in forces due to this porous breakwater and trench-type bottom topography. In addition, from the present results, it may be noted that the load on the submerged tunnel is reduced by adding a submerged horizontal porous plate and asymmetric trench, which is helpful in understanding the role of porous breakwaters and trenches in applications to ocean and coastal engineering. [ABSTRACT FROM AUTHOR]

This article uses scaled physical and numerical modeling to investigate an idealized but complicated problem in which green water impacts a circular cylindrical structure located on top of a fixed box representative of a vessel. A focused wave group was used to overtop the box and generate the green water event, which resembled a plunging wave with air entrainment. The plunger collapsed and ran across the deck before impacting and then scattering from the cylinder. To test the adequacy of the physical modeling, nominally identical experiments were conducted in two different laboratories, in different countries. The numerical modeling comprised computational fluid dynamics (CFD) simulations performed using openfoam. The flow features, the force on the cylinder, and the surface elevation on top of the box are compared in detail across the two physical models and the CFD. Consistent load measurements were obtained from the two physical model tests, with force impulse results differing by less than 10%, underscoring the validity of the results, even accounting for the complexity of flow-structure interactions. A comparison with numerical model results reveals some sensitivity to experimental precision in the flow measurements on top of the box and the green water load. Nonetheless, the overall force impulse discrepancy between experiments and numerical models is within 15%, highlighting that the robustness of the methods was used despite these sensitivities. The sensitivity to CFD mesh and iterating the incident wave to match CFD and experiment are also explored. The agreement between experiment and CFD serves as an example of the utility of CFD for modeling green water loads. [ABSTRACT FROM AUTHOR]

Surface gravity wave interaction of composite wavy porous plate is studied by developing a numerical model using the boundary element method in the context of two-dimensional linear potential theory. Bragg scattering phenomenon is studied by considering the linearized pressure drop condition known as Darcy's law passing through the porous structure. Numerical results are obtained through the boundary element method for the special limiting case of the existing previous literature to authenticate the accuracy of the numerical solution. The influence of wave and structural design parameters such as the number of ripple wavelengths of the wavy plate, relative plate length, structural porosities, and relative submergence depth on hydrodynamics properties such as reflection, transmission, horizontal wave load, and vertical wave coefficients are discussed. The study results of composite wavy porous plate indicate improved hydrodynamic performance as compared to the horizontal porous plate and wavy porous plate. This study is significant for practical applications in coastal engineering environments. [ABSTRACT FROM AUTHOR]

The aim of the paper is the prediction of noise generated by the propeller, hydrodynamic performance and the structural behavior of the marine propeller using two-way fluid–structure interaction (FSI) method at advanced velocities of 6, 8, 10, 12 and 14 Knots. ANSYS-Workbench software is used to establish the coupling between the fluid flow and structural solver. The computed hydrodynamic performance parameters of DTMB 4119 propeller at different advanced velocities and Sound Pressure Level (SPL) at advance coefficient of 0.833 are compared with the data available in the literature and found close agreement. The validated computational methodology is applied for the two-way FSI analysis of the marine propeller. Ffowcs William's–Hawkings (FW–H) model is used to predict the noise spectrum over the frequency range of 0–10 kHz in FSI analysis. Large Eddy Simulation (LES) model is used to capture viscous effects. The speed of the propeller is 1000 rpm and advanced velocity is varied for the systematic study carried out. The effect of advanced velocity on the maximum stress induced in the propeller, deformation of the propeller, acoustic characteristics and hydrodynamic performance of the propeller are studied using FSI method. [ABSTRACT FROM AUTHOR]

The squeezing flow bears a major importance in everyday phenomena and has vast industrial and biomedical applications. The current study looks at the nanofluid flow among two infinite "parallel plates" that are squeezed. The velocity slip and first‐order compound response have been considered in this problem for a clear understanding of their consequences in the flow of nanofluid and heat transport mechanism. This fluid replica thinks about "Brownian motion" and the influences of "thermophoresis" of nanofluid. The novelty of this work lies in exploring the combined effects of first‐order chemical reaction and the velocity slip on unsteady squeezing flow of nanofluid between two parallel plates as one has not yet reported such effects. The prevailing equations are altered into simplified forms by deploying suitable similarity transformations. Then "numerical solutions" of these equations are obtained by applying the fourth‐order "Runge–Kutta method" with the help of the shooting technique. The accuracy is verified by using two different methods and also comparing our data with the available existing literature. The main goal is to study heat and mass transfer through unsteady squeezing plates by the influence of velocity slip and chemical reaction. The consequences of diverse pertinent parameters on fluid flow, thermal, and concentration fields have been explored in this study. With the rise in "velocity slip parameter" from 0 to 1, 81.37% decrease in skin friction coefficient, 15.81% increase in Nusselt number, and 29.13% increase in Sherwood number are observed. Rising values of the chemical reaction parameter from 0.3 to 0.5, the mass transfer coefficient increases by 66.94%. [ABSTRACT FROM AUTHOR]

• A partitioned fluid-structure interaction (FSI) framework is developed. • The meshless Vector Form Intrinsic Finite Element (VFIFE) is innovatively used as a solid solver. • Various benchmarks involving vortex-induced vibration phenomena are studied with the new algorithm. • Strong adaptability and accuracy of the VFIFE method are proved by numerical results. • An experimental case of flow past flexible curtain in a water tank is investigated. The Vector Form Intrinsic Finite Element (VFIFE) is an advanced meshless Lagrangian structural solver. This study introduces a partitioned framework to integrate Arbitrary Lagrangian-Eulerian and VFIFE methods into fluid-structure interaction (FSI) problems featured by large structural displacements and deformations. The VFIFE method enables the FSI simulations with deformable structures due to the nature of Lagrangian particles, which is challenging for traditional computational fluid mechanics techniques. In addition, the VFIFE can be effectively equipped with the partitioned coupling schemes because of the versatility of governing equations. In this algorithm system, several matrix problems in finite element methods and mapping and interpolation in the fluid-structure interface can be avoided. The significant potential of this algorithm in tackling complex FSI problems is demonstrated through various benchmarks, encompassing scenarios like Taylor-Green vortex, flow over a rigid cylinder (Re = 40 ∼ 200), forced vibration of a rigid cylinder, vortex-induced vibration (VIV) of an elastically mounted cylinder, and VIV of a rigid cylinder with an attached flexible cantilever beam. Finally, an experiment on flow past a curtain in a water tank is conducted to further evaluate the precision and stability of the current coupling strategy in three dimensions, demonstrating the feasibility of such methods in flexible structures. [ABSTRACT FROM AUTHOR]

The water hammer, resulting from sudden valve closures or similar operations, is a primary cause of leakage and damage in fluid-conveying pipe systems. This work aims to investigate the reliability sensitivity of fluid-conveying pipes under the water hammer. A reliability model for the fluid-conveying straight pipe, involving uncertainty and fluid-structure interaction, is developed based on the stress-strength interference theory. Then the method of characteristics is employed to analyze the nonlinear behaviors of the pipe. To avoid excessive model evaluations, the Kriging surrogate strategy is used to evaluate rapidly the statistics of nonlinear responses. Furthermore, the Kriging model coupled with the single-loop Monte Carlo simulation is presented for estimating reliability sensitivity indices. The accuracy of results is verified by the Monte Carlo simulation. The results reveal that the proposed method is feasible for the reliability sensitivity analysis of fluid-conveying pipe under the water hammer. Moreover, the wall thickness has the most obvious influence on stress failure, followed by the inner radius, while the pipe length, Young's modulus, density of the pipe material, and Poisson ratio show a low effect. This work can not only guide the safety design of pipe but also enrich the theory and application of statistical analysis and reliability sensitivity evaluation for liquid-conveying pipe systems. • A reliability model for water hammer-induced failure of fluid-conveying pipe is developed. • The reliability model is proposed, incorporating uncertainty and fluid-structure interaction. • The Kriging-based strategy is employed to estimate the response and reliability sensitivity of the pipe. • Different input variables have diverse effects on the nonlinear behavior and reliability of the pipe. [ABSTRACT FROM AUTHOR]

State-of-the-art biomedical applications such as targeted drug delivery and laparoscopic surgery are extremely challenging because of the small length scales, the requirements of wireless manipulation, operational accuracy, and precise localization. In this regard, miniaturized magnetic soft robotic swimmers (MSRS) are attractive candidates since they offer a contactless mode of operation for precise path maneuvering. Inspired by nature, researchers have designed these small-scale intelligent machines to demonstrate enhanced swimming performance through viscous fluidic media using different modes of propulsion. In this review paper, we identify and classify nature-inspired basic swimming modes that have been optimized over large evolutionary timescales. For example, ciliary swimmers like Paramecium and Coleps are covered with tiny hairlike filaments (cilia) that beat rhythmically using coordinated wave movements for propulsion and to gather food. Undulatory swimmers such as spermatozoa and midge larvae use traveling body waves to push the surrounding fluid for effective propulsion through highly viscous environments. Helical swimmers like bacteria rotate their slender whiskers (flagella) for locomotion through stagnant viscid fluids. Essentially, all the three modes of swimming employ nonreciprocal motion to achieve spatial asymmetry. We provide a mechanistic understanding of magnetic-field-induced spatiotemporal symmetry-breaking principles adopted by MSRS for the effective propulsion at such small length scales. Furthermore, theoretical and computational tools that can precisely predict the magnetically driven large deformation fluid–structure interaction of these MSRS are discussed. Here, we present a holistic descriptive review of the recent developments in these smart material systems covering the wide spectrum of their fabrication techniques, nature-inspired design, biomedical applications, swimming strategies, magnetic actuation, and modeling approaches. Finally, we present the future prospects of these promising material systems. Specifically, synchronous tracking and noninvasive imaging of these external agents during in vivo clinical applications still remains a daunting task. Furthermore, their experimental demonstrations have mostly been limited to in vitro and ex vivo phantom models where the dynamics of the testing conditions are quite different compared the in vivo conditions. Additionally, multi-shape morphing and multi-stimuli-responsive modalities of these active structures demand further advancements in 4D printing avenues. Their multi-state configuration as an active solid-fluid continuum would require the development of multi-scale models. Eventually, adding multiple levels of intelligence would enhance their adaptivity, functionalities, and reliability during critical biomedical applications. [ABSTRACT FROM AUTHOR]

An exact similarity solution is worked out for fluid motion in the vicinity of a cylindrical surface in an electrically conducting viscoelastic fluid obeying the Jeffrey model. Cylindrical surface expands axially with linear velocity and has a prescribed surface temperature. The present analysis focuses on the partial slip assumption which gives rise to a nonlinear case Robin-type (mixed) boundary condition in axial velocity. In contrast to a previously published study (J. Mech., vol 31, pp. 69–78, 2015) which only reported local similarity solutions in no-slip case, the present work provides an exact similarity analysis by defining a quadratic surface temperature. The effects of the magnetic field and Joule heating on the momentum and thermal transport phenomena are also scrutinized. A numerical routine is used to solve the equation accurately for a wide range of fluid parameters, including ranges that could not be handled by previous approximate analytical methods that were limited to the no-slip limit. The influences of viscoelasticity and partial slip on the flow behavior are investigated, and the coefficient of skin friction for a Jeffrey fluid is calculated. Obtained results are consistent with the previously published works under special situations. The case of flat surface, which can be obtained as a limiting case of the model, is not even explored in the past. [ABSTRACT FROM AUTHOR]

Deformable wave energy converters have significant potential for application as flexible material that can mitigate structural issues, while how to design the dimensions and choose an optimal deployment location remain unclear. In this paper, fully coupled computational fluid dynamics and computational solid mechanics were used to simulate the dynamic interactions between ocean waves and a deformable wave energy converter. The simulation results showed that the relative length to wave, deployment depth and aspect ratio of the device have significant effects on the energy conversion efficiency. By calculating the energy captured per unit width of the device, the energy efficiency was found to be up to 138%. The optimal energy conversion efficiencies were achieved when the structure length was 0.25, 0.5 or 0.75 of the dominating wavelength and submerged at a corresponding suitable depth. The aspect ratio and maximum stress inside the wave energy converter showed a nonlinear trend, with potential optimal points revealed. The simulation approach and results support the future design and optimisation of flexiable wave energy converters or other marine structures with notable deformations. [ABSTRACT FROM AUTHOR]

In this paper, we study the dynamics of a small rigid body in a viscous incompressible fluid in dimension two and three. More precisely we investigate the trajectory of the rigid body in the limit when its mass and its size tend to zero. We show that the velocity of the center of mass of the rigid body coincides with the background fluid velocity in the limit. We are able to consider the limit when the volume of the rigid bodies converges to zero while their densities are a fixed constant. [ABSTRACT FROM AUTHOR]

This study presents seismic performance of two existing at-grade industrial liquid-storage tanks located in the Eastern part of Marmara region, which is a high seismic region in Turkey. The first tank is self-anchored (unanchored) and has been in service for 44 years, while the other tank is mechanically anchored to a reinforced concrete foundation and has been in service for 50 years. Tanks seismic performance is evaluated using tank time-history earthquake analyses with recorded ground motions scaled for each tank site. The liquid content was included in the developed model using provisions of API 650. Tanks base uplift, sliding on the foundation, tank shell and bottom plate damage, and demand on tank anchorage were determined. The results shows that self-anchored tank has base plate uplift and sliding that are larger than the allowable limits while the mechanically anchored tank has acceptable seismic performance with potential seismic damage of tank anchorage system. The findings of this study contribute valuable insight into the seismic performance of existing liquid storage tanks in the region under new seismic regulations and increased seismic loads than those used for their design. [ABSTRACT FROM AUTHOR]

Shield tunneling processes can result in accidents like water inrush and collapse due to instability in the tunnel face. This paper conducts a systematic investigation of the deformation features and failure mechanism of subsea shield tunnels with different burial depths crossing fault zone. The research entails combing theoretical analysis, numerical simulation, and data mining with the second subsea tunnel in Jiaozhou Bay, Qingdao. The impact of the shallow and deep burial depths on the damage modes of the shield tunnel face is analyzed from the perspective of the pressure arch effect. When the tunnel burial depth exceeds the limit, the overlying rock of the tunnel will form a pressure arch that supports the overlying rock. The study investigates the impact of various factors on the tunnel face's failure modes using a fluid-structure interaction approach. Among them, as the thickness of the overlying bearing stratum increased, the displacement of the tunnel face initially decreased but later increased. The increase of cohesion and internal friction angle contributed to decreasing the displacement of the tunnel face, while seawater depth and tunnel diameter exhibited diverse effects. In the grey correlation analysis, the seawater depth exhibited the most sensitive impact on the pressure arch height. [ABSTRACT FROM AUTHOR]

The paper investigates the phenomenon of the aeroelastic response of flexible thin airfoils under various angles of attack (AOAs) and flow velocities through wind tunnel experiments and numerical simulations. The vibration modal characteristics are explored, including vibration frequencies, amplitudes, modal transition, and instantaneous characteristics. Vibration is directly measured using non-contact laser sensors, and the numerical model is appropriately configured to simulate the fluid–structure interaction (FSI) problem under large deformation. Experiments cover a range of AOAs (1 ° – 20 °) and incoming velocities (from 10 to 73 m / s), with dynamic responses measured using four laser sensors. Both average and instantaneous modal response features are analyzed, revealing multi-modal characteristics as velocity and AOA increase. The vibration mode transitions from pure bending to higher-order modes as incoming velocity increases. Specifically, at higher velocities and increased AOA, the high-order vibration component shifts from bending-torsional coupled mode to pure-torsional mode. Comparison of vibration frequencies between experimental measurements and finite element method simulations highlights significant shifts, particularly in the pure-torsional mode. Furthermore, employing commercial software ANSYS CFX and ANSYS Mechanical, a two-way three-dimensional FSI model successfully replicates flutter boundaries observed experimentally at 1 ° AOA and approximately incoming velocity 73 m/s. This FSI model is extended to simulate the multi-modal vibrations at 15 ° AOA, yielding insights into flow phenomena contributing to multi-modal vibration at this AOA. An explanation is provided for the multi-modal vibration phenomenon observed in the experiments based on the above insight. Finally, the differences between the experimental and numerical simulations are speculated upon. [ABSTRACT FROM AUTHOR]

This paper addresses the fluid–structure interaction problem, with an interest on the interaction of a gravity wave with a flexible floating structure, anchored to a seabed of constant depth. To achieve this goal, we make use of the model equations, namely, the Navier–Stokes equations and the Navier–Lamé equation, as well as the associated the boundary conditions. Applying the multi-scale expansion method, these set of equations are reduced to a pair of nonlinearly coupled complex cubic Ginzburg–Landau equations (CCGLE). By applying the proposed modified expansion method, the group velocity dispersion and second-order dispersion relation are deduced. In the same vein, modulation instability (MI) is investigated as a mechanism of formation of pulse trains in fluid–structure system using a CCGLE. For the analytical analysis, we made use of the inverse scattering method to find analytical solutions to the coupled nonlinear equations. Through that method, the obtained solutions depict rogue-shaped waves. Our results suggest that uncontrolled MI within the interaction between a flexible body and gravity waves in viscous flow may be considered as the principal source of many structural ruptures, which are the first cause of critical damage due to the great energy and unpredictability of rogue waves. The present work aims to provide tools to model a wide range of physical problems regarding the interaction of surface gravity waves and an offshore-anchored structure, and it aims to be essential to our understanding of the nonlinear characteristics of offshore structures in real-sea states. [ABSTRACT FROM AUTHOR]

In order to study the vortex-induced vibration (VIV) characteristics of rigidly connected four-cylinder systems and the suppression of vortex-induced vibration by nonlinear energy sinks (NESs), a fluid–structure coupling dynamic simulation model of a two-degree-of-freedom rigidly connected four-cylinder system is established based on computational fluid dynamics, structural dynamics, and overset mesh technology. The accuracy of the numerical model established in this paper is verified by comparing with the experimental data of literatures. The results show that the dimensionless vertical amplitude of the four-cylinder system decreases with increase in the inflow angle, the reduced velocity advance of the maximum vertical amplitude moves forward and the frequency "lock-in" interval is shortened. Among them, the maximum amplitude at U r = 7 is 0.75 when the inflow angle is 0°, and the maximum amplitude is 0.54 at U r = 6.5 when the inflow angle is 45°. The corresponding frequency "lock-in" interval ranges from U r = 4.5 – 7 change to U r = 5 – 6.5. The NES can absorb the cylinder vibration energy, and when the NES parameter β = 0.1 , ξ = 0.8 , γ = 0.8 , the maximum vertical of the four-cylinder system with inflow angle of 0° can be reduced by 76%. [ABSTRACT FROM AUTHOR]

The structural response of a rudder in the wake of a marine propeller is investigated by one-way fluid–structure interaction approach. The unsteady pressure field gathered by detached eddy simulations is provided to a structural solver for the computation of deformations and stresses of the rudder. The study compares the structural response of the rudder at neutral and two equal and opposite rotations, which are representative of design conditions in straight motion and maneuvering conditions that are experienced under the action of the autopilot for course control or weak maneuvering. The analysis sheds light on the different structural behavior at the two opposite rotation angles, caused by asymmetrical variation along the span of the rudder of the angle of attack induced by the propeller slipstream, by considering the different role played by the tip and hub vortical systems. The test case consists of a rudder with a rectangular plane area and National Advisory Committee for Aeronautics 0015 sectional profile located past the E779A propeller. The propeller operates at low loading conditions, and the rudder is set at incidence δ = 0 ∘ , ± 4 ∘. The study shows that the response of the rudder is driven by flap and torsion and is asymmetric for the two and opposite rotations. The mean deformation and vibratory response are magnified for δ = − 4 ∘ by at least 70% and 20% for the lateral and edgewise deflections, respectively, with respect to the opposite rudder incidence. In general, the excitation generated by the tip vortex is stronger than that of the hub vortex. In the most critical condition, at δ = − 4 ∘ , the excitation associated with the tip vortex is nearly double that of the hub vortex. [ABSTRACT FROM AUTHOR]

The onset of flow-induced oscillations in valve-like configurations remains not completely understood, despite the wide relevance in fluid transport across human physiology and various industrial applications. The present work explores the excitation mechanisms of self-sustained oscillation with key operating parameters in a general-purpose configuration by means of high-fidelity simulations. The investigation is carried out with a partitioned framework that resolves the fluid field by a finite-difference fractional step scheme, discretizes the structural domain via an isogeometric method, and considers an immersed boundary forcing through the interpolation/spreading kernel built by moving-least squares. Our findings confirm the onset of flapping motion in valvular shells, jointly influenced by geometric parameters, structural properties, and flow conditions. Specifically, at a Reynolds number (Re) of 800 and shell aspect ratio of 1.0, a critical reduced velocity exists at around 6, bifurcating static and periodic oscillation modes. After this criterion, flexible shells flutter in the third-plate-mode natural frequency, with oscillation amplitudes approaching an asymptotic value, coupled with intensified vortex shedding, as the reduced velocity increases. Re mainly imparts a destabilizing effect on the fluid-shell system; a lower Re suppresses flow-induced vibrations through viscous dissipation, while a higher Re introduces three-dimensional complexities, asymmetrical oscillations, and quasi-periodicity in the flapping dynamics, especially within the critical regime of reduced velocity. The impact of shell aspect ratio is intricate; in contrast, the case with an aspect ratio of 1.3 displays more intensive flapping motion compared to the reference case of 1.0, whereas further increasing to 1.6 mainly shows stabilizing effects in the shell dynamics. [ABSTRACT FROM AUTHOR]

In this work, an algorithm for topology optimization of incompressible structures is proposed, in both small and finite strain assumptions and in which the loads come from the interaction with a surrounding fluid. The algorithm considers a classical block-iterative scheme, in which the solid and the fluid mechanics problems are solved sequentially to simulate the interaction between them. Several stabilized mixed finite element formulations based on the Variational Multi-Scale approach are considered to be capable of tackling the incompressible limit for the numerical approximation of the solid. The fluid is considered as an incompressible Newtonian fluid flow which is combined with an Arbitrary-Lagrangian Eulerian formulation to account for the moving part of the domain. Several numerical examples are presented and discussed to assess the robustness of the proposed algorithm and its applicability to the topology optimization of incompressible elastic solids subjected to Newtonian incompressible fluid loads. [ABSTRACT FROM AUTHOR]

This study examines the two-phase nanofluid magnetohydrodynamic (MHD) boundary layer flow model with heat absorption or generation and chemical reaction via porous media due to an exponential stretching sheet using the Haar wavelet collocation method (HWCM). First, the governing nonlinear partial differential equations (PDEs) are transformed into coupled, highly nonlinear, ordinary differential equations (ODEs) using similarity transformations. Then the coupled ODEs are translated from the infinite domain [0, ∞ ) to the finite domain [0, 1] via coordinate transformation because the wavelet plays a crucial role in [0, 1]. The obtained equations are solved using HWCM. The impacts of the physical parameters are discussed using tables and graphs. It was found that the Nusselt number R e x − 1 / 2 N u x is a decreasing function of the magnetic field, porous media parameter, heat generation or absorption parameter, and chemical reaction parameter. [ABSTRACT FROM AUTHOR]

The reciprocal energy and enstrophy transfers between normal fluid and superfluid components dictate the overall dynamics of superfluid 4He including the generation, evolution and coupling of coherent structures, the distribution of energy among lengthscales, and the decay of turbulence. To better understand the essential ingredients of this interaction, we employ a numerical two-way model which self-consistently accounts for the back-reaction of the superfluid vortex lines onto the normal fluid. Here we focus on a prototypical laminar (non-turbulent) vortex configuration which is simple enough to clearly relate the geometry of the vortex line to energy injection and dissipation to/from the normal fluid: a Kelvin wave excitation on two vortex anti-vortex pairs evolving in (a) an initially quiescent normal fluid, and (b) an imposed counterflow. In (a), the superfluid injects energy and vorticity in the normal fluid. In (b), the superfluid gains energy from the normal fluid via the Donnelly–Glaberson instability. [ABSTRACT FROM AUTHOR]

Background: Intracranial aneurysm is a pathology related to the biomechanical deterioration of the arterial wall. As yet, there is no method capable of predicting rupture risk based on quantitative, in vivo mechanical data. This study is part of a large-scale project aimed at providing clinicians with a non-invasive, patient-specific decision support tool, based on the in vivo mechanical characterisation of the aneurysm wall. To this end, an original arterial wall deformation device was developed and tested on polymeric phantom arteries. Concurrently, a computational model coupled with the experimental study was developed to improve understanding of the interaction between the arterial wall deformation device and the aneurysm wall. Objective: An original procedure was implemented to validate the numerical model against experimental results. Methods: The deformation induced by the device on the polymeric phantom arteries is quantified by Digital Image Correlation. The Fluid-Structure Interaction between the device and the arterial wall was modelled numerically with the Finite Element method. The validation procedure encompasses the extraction and the interpolation of the numerical results. The computed strains were compared with the data measured experimentally. Results: The numerical results interpolated on the experimental reference image were associated with several deformation device locations. These configurations induced strains and displacements ranges that included the experimental results, which validates the proposed model. Conclusions: The reliability of the procedure was validated with various study cases and artery materials. The procedure could be extended to experimental studies involving more complex phantom arteries in terms of shape and wall heterogeneity. [ABSTRACT FROM AUTHOR]

In this paper, the effectiveness of seismic isolation using lead rubber bearings (LRBs) and friction pendulum systems (FPSs) for slender and broad, grounded and elevated tanks (two seat locations of isolation systems in elevated tanks) is investigated under bi-directional excitation of up to 10 records of earthquakes. An analytical mechanical model for a flexible, concrete cylindrical tank, taking into consideration the effect of wall mass and sloshing, is used. The assumptions underlying the mechanical model are basic equations of the motion according to the theory of fluid dynamics. So, the assumptions are more realistic and the results therefore are more accurate than the previous models. The results show that by selecting the best mechanical properties of base isolation systems, reductions of seismic base shear in the grounded broad tanks are around 35% and 30% and for the grounded slender tanks are around 55% and 58% in the x- and y-directions, respectively. Maximum total hydrodynamic pressure is reduced considerably by about 40% on average in all grounded and elevated models. As a result of isolation, elevated tanks are concluded to be better candidates in terms of more effective application of seismic isolation. [ABSTRACT FROM AUTHOR]

Hemodynamic forces are felt by the biomechanical receptors of the arterial wall to give an appropriate response to maintain homeostasis. On the other hand, baroreceptors are a type of biomechanical receptors that are sensitive to abnormal stretch sizes. It is very important to predict the distribution of stress and strain caused by the hemodynamic field to the vessel wall in pressure-sensitive areas to evaluate the function of these receptors. In the present study, a three-dimensional (3-D) model of the aortic arch is presented. The geometry was reconstructed based on the CT images. Also, numerical analysis was performed using the fluid-structure interaction method. First, the hemodynamic field containing the pressure and velocity distribution in the blood area was obtained. Then, the deformation and stress fields in the solid domain were analyzed. The results show that the highest vertical stress occurs in the posterior supra aorta. So, the amount of this maximum vertical stress increases up to 5 kPa in some places; these points have higher tensions, and they can be susceptible to rupture and aneurysm diseases. Higher normal stress happened at the aortic root and the supra-aortic branches and reached approximately 200 kPa at Peak Systole. Also, the highest amount of strain occurs in the posterior supra aorta, reaching 0.001. [ABSTRACT FROM AUTHOR]

Based on the finite element software Ansys Workbench,the finite element model of the motion of the bump foil dynamic pressure gas bearing in the compressible fluid medium was established,and the fluid-structure coupling numerical simulation of the motion state of the bearing was carried out by using the 6DOF dynamic grid calculation method.The influence of different speed and bump foil structure parameters (length ratio,height and thickness of bump foil) on bearing performance was discussed.The simulation results show that the distribution of the bearing gas film pressure corresponds to the deformation of the flat foil,indicating that the proposed fluid-structure coupling method can effectively reflect the lubrication state of the bump foil dynamic pressure gas bearing.With the increase of rotational speed,the dynamic pressure effect of the bearing is enhanced continuously,the load-carrying capacity increases,and the structural deformation of flat foil is increased,resulting in fluctuations in the convergence zone of gas film pressure.With the increase of the length ratio of the bump foil and the thickness of the bump foil,the load-carrying capacity increases rapidly at first and then becomes stable,while the height of the bump foil has little effect on the load-carrying capacity,indicating that the load-carrying capacity can be improved by increasing the length ratio of the bump foil and the thickness of the bump foil appropriately. [ABSTRACT FROM AUTHOR]

The reliable exchange of data is a crucial issue for the loose coupling of computational fluid dynamics (CFD) and computational structural mechanics (CSM) modules in fluid–structure interaction (FSI) applications. This paper presents a comparison between two methods for mapping the traction field across mismatching grids, namely the RIBES method and the preCICE algorithm, both based on radial basis function (RBF) interpolation. The two methods demonstrate different degrees of control over balance preservation during mapping, with the RIBES algorithm exhibiting greater efficacy. Test benches are a parametric double curved geometry and a wind tunnel mock-up. In this second case, forces from mapping are used to load a CSM model to retrieve stress and displacement fields. Differences in FEM results are appreciable although not significant, showing a correlation between the accuracy of balance preservation during data mapping and the structural output. [ABSTRACT FROM AUTHOR]

Cylindrical shell structures have excellent structural properties and load-bearing capacities in fields such as aerospace, marine engineering, and nuclear power. However, under high-pressure conditions, cylindrical shells are prone to cracking due to impact, corrosion, and fatigue, leading to a reduction in structural strength or failure. This paper proposes a static modeling method for damaged liquid-filled cylindrical shells based on the extended finite element method (XFEM). It investigated the impact of different initial crack angles on the crack propagation path and failure process of liquid-filled cylindrical shells, overcoming the difficulties of accurately simulating stress concentration at crack tips and discontinuities in the propagation path encountered in traditional finite element methods. Additionally, based on fluid-structure interaction theory, a dynamic model for damaged liquid-filled cylindrical shells was established, analyzing the changes in pressure and flow state of the fluid during crack propagation. Experimental results showed that although the initial crack angle had a slight effect on the crack propagation path, the crack ultimately extended along both sides of the main axis of the cylindrical shell. When the initial crack angle was 0°, the crack propagation path was more likely to form a through-crack, with the highest penetration rate, whereas when the initial crack angle was 75°, the crack propagation speed was slower. After fluid entered the cylindrical shell, it spurted along the crack propagation path, forming a wave crest at the initial ejection position. [ABSTRACT FROM AUTHOR]