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The large-scale management of ditches and implementation of land projects in loess areas have increased the arable land area but have caused considerable engineering issues, resulting in severe soil erosion. In this study, field tests were performed at different time scales, a control group was established, organic material–plant joint restoration technology was proposed as an optimized management measure, and the erosion control mechanism and restoration mode of organic material–plant joint restoration technology were analyzed. Based on the obtained experimental data, a Water Erosion Prediction Project (WEPP)-based hydraulic erosion model was constructed, sensitivity parameters were calibrated, and the soil erosion intensity and corresponding spatial distribution in the watershed of the study area were simulated via the geo-spatial interface for WEPP (GeoWEPP) after organic material–plant joint restoration technology was adopted to predict the effect of optimized management measures. The results showed that among the slopes with different restoration measures, organic material–plant joint restoration technology effectively controlled loess slope erosion, and the average erosion modulus of the organic material–grass and shrub transplantation slope reached only 23.37 t/km2, which is a decrease of 97.68% relative to the traditional grass–shrub protection slope. Moreover, the sand content of the joint restoration slope was reduced by 392.41 g/L relative to the bare slope, reaching only 0.29 g/L, and the runoff yield was reduced by 8.88 L/min. The GeoWEPP modeling results revealed that the total runoff yield and average annual erosion modulus of the watershed were lower after joint restoration than during the prerestoration period. Similarly, the total runoff yield of the watershed was 4.6%, the simulated 10-year average annual total sand production reached 2048.3 t, and the average annual erosion modulus was 582.75 t/km2, which is 52.15% lower than that under untreated conditions. This study provides a new strategy for solving soil erosion problems and restoring the ecology of slopes after managing ditches and implementing land projects. [ABSTRACT FROM AUTHOR]

This document is a compilation of various scientific articles and studies related to coastal engineering, beach nourishment, and shoreline dynamics. The references cover a wide range of topics, including the impacts of nourishment on shoreline response, the use of nature-based solutions for coastal erosion, and the effects of submerged breakwaters. They also discuss the role of waves, sediment transport, and beach profile change in beach nourishment, as well as the effects of nourishment on benthic fauna and the vulnerability of beaches to sea level rise. These references provide valuable information for researchers and decision-makers interested in these subjects. [Extracted from the article]

In field hydraulic fracturing operation of shale gas development, the high pressure and large displacement liquid-particle two-phase fracturing fluid can be forced to change direction many times through high-pressure double-elbow, and be transported from the outlet pipeline of the fracturing pump to the main pipeline. The high-pressure double-elbow is prone to be affected by erosion wear and Fluid-Structure Interaction (FSI), resulting in perforation and fracture, posing a potential safety threat to field operation. In this study, we conducted the erosion wear experiments on 35CrMo steel used for high-pressure double-elbow in shale-gas fracturing. The erosion rates under different impact angles and flow velocities were obtained, and proposed a novel model of erosion prediction for high-pressure double-elbow. Then the numerical investigation was employed to conduct a comprehensive analysis of erosion wear, structural stress and deformation by the coupling of Computational Fluid Dynamics (CFD) and Finite Element Analysis (FEA). The effects of structural parameters such as connection straight pipe length, pipe inner diameter and fluid turning direction were discussed. The results indicate that with the increase of connection straight pipe length, the flow erosion decreases first then varies little, and the deformation gradually increases. Slight erosion wear but large structural stress and deformation in major inner diameter pipe. And the minimum degree of erosion and flow-induced deformation present with the fluid turning direction of double-elbow as 0°. The study can provide references for the design, installation and detection of high-pressure double-elbow and ensure safety in the process of shale gas fracturing.

The Brahmaputra River has a dynamic, highly braided channel pattern with frequent river bar formation, making it morphologically very dynamic, especially during the monsoon season with high discharge and sediment load. To understand how the river changes over time, this study focused on two stretches: Palasbari-Gumi and Dibrugarh. Using 2D morphological models (MIKE-21C), the study aimed to predict erosion patterns, plan protective measures, and assess morphological changes over short-term (1 year), medium-term (3 year), and long-term (5 year) periods. Model runs were conducted to predict design variables across these river reaches, encompassing different hydrological scenarios and development-planning scenarios. The coarse sand fraction yielded mean annual sediment load predictions of 257 Mt/year for the 2021 hydrological year and 314 Mt/year under bankfull discharge conditions in the Palasbari-Gumi reach. In the Dibrugarh reach, the corresponding values were 78 Mt/year and 100 Mt/year. Notably, historical records indicate an annual sediment load of 400 Mt/year in the Brahmaputra River. The model results were compared to measurements from Acoustic Doppler Current Profilers (ADCP), showing good accuracy for flow velocities, flood levels, and sediment loads. Discrepancies in peak model velocities compared to ADCP measurements remain consistently below 9% across the majority of recorded data points. The predicted flood levels for the bankfull discharge condition exhibited an outstanding accuracy, reaching nearly 91% at the Palasbari-Gumi site and a notable 95% at the Dibrugarh site. This study has presented a valuable methodology for enhancing the strategic planning and implementation of river training endeavours, particularly within the dynamic and highly braided channels of rivers such as the Brahmaputra River. The approach leverages predictive models to predict morphological changes over a 2–3 years timeframe, contributing to improved river management.

The throttle valve is vital in the oil and gas production stage, designed to decrease natural gas pressure at the wellhead to match transportation pipeline standards. During this process, its flow rate sharply increases, leading to erosion by sand particles discharged from the well's bottom. To predict the cage throttle valve's service life, we established and validated an erosion model for its throttling trim through tests, calculating the erosion wear rate using CFD simulation software. Tests reveal that WC–Co cemented carbide displays typical brittle material traits; its highest erosion wear rate occurs at a 90° impact angle, with a velocity index of 2.4. Study findings indicate the most severe erosion at the smallest orifice of the cage, with the erosion wear rate increasing linearly as particle mass flow rate rises. Consequently, the throttle trim should be inspected and replaced within two years for low mass flow rates of sand particles, or within 3 to 6 months for high mass flow rates. [ABSTRACT FROM AUTHOR]

Erosion equations were developed to predict the material removal of polyurethane coatings on carbon fiber reinforced plastic (CFRP) surfaces and validated through experimental data. The effects of abrasive properties, process parameters, and organic coating properties (such as fracture toughness and hardness) were considered in the equations. As the erosion angle increased, elastoplastic deformation in the oblique direction and repeated "deformation" in the normal direction were the main reasons for material removal. The ductile erosion behavior was confirmed by experimental data because the maximum erosion rate occurred at an incident angle of 30°. The coefficient and index in the equations were determined by experimental data, and the equations were verified. The developed equations could accurately predict the quantity loss of organic coatings under different particle sizes and particle velocities, and the erosion equations were in good agreement with the experimental data. [ABSTRACT FROM AUTHOR]

Erosion is an essential deterioration mechanism in compressors of jet engines. Erosion damage predictions require the determination of erosion rates through flat plate experiments. The applicability of the erosion rates is limited to conditions that are comparable to the prevailing boundary conditions of the flat plate experiment. A performed dimensional analysis enables the correct transfer of the flat plate erosion rates to the presented physical calculation model through limits in spatial and time resolution. This efficient approach avoids computationally intensive single-impact computations. The approach features a re-meshing procedure that adheres to the limits derived by the dimensional analysis. The computation approach is capable of describing local geometry changes on cascade compressor blades which are exposed to erosive particles. A linear erosion cascade experiment performed on NASA Rotor 37 provides validation data for the calculated erosion-induced shape change. Arizona Road Dust particles are used to deteriorate Ti-Al6-4V compressor blades. The experiment is performed at an incidence of i = 7°and Ma = 0.76 representing ground idle conditions. The presented parametric study for element size and time step revealed preferable values for the presented computation. Calculations performed with the determined values showed that the erosion prediction is within the measurement tolerance of the experiment and, therefore, high accordance between the computation and the experiment is achieved. To extend the current state of the art, it is demonstrated that the derived discretization is decisive for the correct reproduction of the eroded geometries and fitting parameters are no longer needed. The good agreement between the experimental measurements and the calculated results confirms the correct application of the physical model to the phenomenology of erosion. Thus, the presented physical model offers a novel approach to adapting deterioration mechanisms caused by erosion to any compressor blade geometry.

Soil, one of the non-renewable resources on this planet, is being depleted at an alarming rate due to various anthropogenic activities. The effect of soil erosion could range from on-site ecosystem fragmentation to off-site reservoir storage capacity loss. Though soil erosion is caused by various agents such as wind, water, etc., water erosion is the major type. Heavy rainfall during the monsoons and the relatively thin cover of soil over the bedrock aggravates the damage potential of this form of erosion in the state of Kerala, India. Water-induced soil erosion in the Bharathapuzha river basin in Kerala, which is blessed with cultivable land resources and intensive agricultural activities, has been undertaken for quite long and has started impacting agricultural activities, drinking water supply, and reservoir storage capacity in the basin. In this background, this study was taken up to assess the effects of climate and land use–land cover dynamics on soil erosion in the Bharathapuzha river basin over the last three decades. Soil erosion from the river basin was estimated by the Revised Universal Soil Loss Equation (RUSLE), and these estimates were verified with the observed sediment load in the Bharathapuzha river at the Kumbidi river gauging station. The storage capacity loss of some of the reservoirs located in the river basin, estimated by the Integrated Bathymetric Survey (IBS), was compared with the likely storage capacity loss of these reservoirs estimated based on soil erosion from the catchment areas upstream. Soil loss from the river basin for a future period was predicted using projections of future climate under two Representative Concentration Pathways (RCP 4.5 and RCP 8.5) from four regional climate data experiments and future land use–land cover. Annual soil loss estimation maps for 2020 and 2035 under RCP4.5 and RCP8.5 reveal the urgent necessity to plan and implement soil conservation measures in the erosion hotspots, especially in the Malampuzha, Anamala, and Attapady sub-basins. [ABSTRACT FROM AUTHOR]

In field hydraulic fracturing operation of shale gas development, the high pressure and large displacement liquid-particle two-phase fracturing fluid can be forced to change direction many times through high-pressure double-elbow, and be transported from the outlet pipeline of the fracturing pump to the main pipeline. The high-pressure double-elbow is prone to be affected by erosion wear and Fluid-Structure Interaction (FSI), resulting in perforation and fracture, posing a potential safety threat to field operation. In this study, we conducted the erosion wear experiments on 35CrMo steel used for high-pressure double-elbow in shale-gas fracturing. The erosion rates under different impact angles and flow velocities were obtained, and proposed a novel model of erosion prediction for high-pressure double-elbow. Then the numerical investigation was employed to conduct a comprehensive analysis of erosion wear, structural stress and deformation by the coupling of Computational Fluid Dynamics (CFD) and Finite Element Analysis (FEA). The effects of structural parameters such as connection straight pipe length, pipe inner diameter and fluid turning direction were discussed. The results indicate that with the increase of connection straight pipe length, the flow erosion decreases first then varies little, and the deformation gradually increases. Slight erosion wear but large structural stress and deformation in major inner diameter pipe. And the minimum degree of erosion and flow-induced deformation present with the fluid turning direction of double-elbow as 0°. The study can provide references for the design, installation and detection of high-pressure double-elbow and ensure safety in the process of shale gas fracturing., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

The structural components prone to erosion damage often exhibit irregular and complex shapes. Predicting erosion rates for such irregular geometries is a field that needs more attention, since it can be used to evaluate the performance of the component. This study aims to develop an evaluation method for predicting erosion rates of components with complex geometry. Standard erosion tests were performed on small plates to investigate the effects of different impact angles and particle velocities on the erosion rate of the target material. Based on these test results, the Newton iteration method was employed to determine the parameters of the Tabakoff and Grant erosion model. Moreover, these parameters were used in computational fluid dynamics simulation of components with complex geometries. Besides, a model was developed to convert the erosion rate density into erosion rate in numerical simulation, allowing quantitative comparison of simulation results with experimental data. The calibration of the erosion model parameters was conducted by using 1060 aluminum alloy specimens. The predicted erosion rate changes with impact angle showed consistency good agreement with the testing data. Subsequently, the erosion rate of a simplified similar structure for aircraft engine blade made of 1060 aluminum alloy was predicted and verified. • Determined optimal Tabakoff and Grant erosion model parameters for 1060Al by standard erosion tests. • Quantitative evaluation of erosion rates for components with complex geometry. • A model for conversion of erosion rate density to erosion rate was proposed. • Effectively predicted erosion rates for a simplified structure of aircraft engine blade. [ABSTRACT FROM AUTHOR]

[Objectives] The elbow is a common component of ship piping system. Efforts have been made in order to predict the elbow erosion accurately.[Methods] In this paper,the numerical simulation is conducted to calculate and analyze the flow field inside the pipe. From the two aspects,i.e. the influence of the turbulence model on the prediction of the flow field in the elbow and the influence of turbulence model on elbow erosion calculation,intensive research into the method to predict the erosion of elbow by solid and liquid flows.[Results] The results show that the SST k-ω turbulence model,together with the Oka erosion model,can accurately predict the flow field distribution in the elbow. Turbulence model brings a significant impact on the abrasion calculation,where it affects the calculated value of final erosion and also makes a great difference in the distribution of predicted relative erosion.[Conclusions] The obtained results can provide guidance for future pipe erosion prediction.

The conversion of native forest to the tea plantation and cropland has intensified throughout the Coonoor watershed of the Nilgiris region over the past few decades. The current study investigates the severity of land cover changes including deforestation activities in the Coonoor watershed region as a result of urbanization, along with the establishment of recreational parks, resorts and tea plantations. In order to analyse the changes, a widely used soil erosion model say Revised Universal Soil Loss Equation (RUSLE) is opted to estimate the average soil loss. Therefore, this work marks the impact of land-use changes on land degradation and the consequent vital natural phenomenon like soil erosion. The change detection was carried out for over 14 years period from 2005 to 2018. Landsat images of corresponding years were classified using the supervised classification technique. The C-factor (cover and management factor) for the corresponding periods were also identified. Conversion of forest land into tea plantations, wastelands and settlements significantly decrease the soil organic matter (SOM) and hydraulic conductivity (HC) of the soil, which leads to a difference in the K-factor (soil erodibility factor) throughout the study period, whereas the R-factor (rainfall and runoff factor) and LS-factor (length-slope factor) were considered to be constant throughout the period. Results indicate the annual soil loss during the period from 2000 to 2018 on each land use/cover classes. viz., tea plantations, 223.26 km2; settlement, 163.35 km2; open forest, 799.02 km2; dense forest, 1158.48 km2; and barren land, 27.18 km2. The total sediment yield in the study area was found to have oddly increased due to the land use/cover changes. The significant rise of soil erosion was found evitable in the deforested region which was converted to infrastructure and wasteland. [ABSTRACT FROM AUTHOR]

A correct understanding of the variation pattern of water and sediment conditions as well as erosion and deposition characteristics in the reach between Three Gorges Dam and Gezhou Dam is essential for studying the many engineering problems in the reach. In this study, abundant water-sediment topographic data were analyzed, and the application of the theory of sediment incipient motion in erosion prediction was discussed. Owing to reservoir construction in the upper reaches of the Yangtze River and the successive operation of the two major hubs, the annual runoff in the reach was slightly reduced, the monthly average runoff was redistributed by “peak load shifting?” the annual sediment discharge declined considerably, and the water-sediment relationship in the reach was significantly changed. The cumulative erosion and deposition quantity in the reach was under short- and long-term control by the extreme hydrological conditions and scheduling of the hubs. In terms of time, there were apparent phased characteristics, in terms of space, some sub-reaches were in an active state. The bed sediment was refined and coarsened successively with the operation of the hub. The incipient critical condition curve was drawn based on Sha's incipient velocity equation, and the estimation of the maximum particle size of movable bed sediment or critical water flow of the cross-section provided a reference for predicting the possibility of riverbed erosion. [ABSTRACT FROM AUTHOR]

Sand erosion is a serious problem to be solved in the oil and gas industry. During the transportation of oil and gas, different multiphase flow patterns may occur due to variations of factors, such as the conveying speed, fluid property and pipe geometry. The present work aims at developing a novel framework to predict sand erosion in elbows for multiphase flows. Firstly, the effects of flow patterns on sand erosion are analyzed. Based on these analyses, the erosion model for each specific flow pattern is established. Combining with the basic penetration ratio in gas flow and erosion coefficients, the erosion models of different flow patterns can be unified as an integrated model. Then, the accuracy of the integrated model is examined by 108 experimental cases. After the experimental validation, an optimal coefficient is proposed to further optimize the integrated model. A comparison between the optimized integrated model and the non-optimized integrated model is performed. The results demonstrate that the optimized integrated model performs well in improving the accuracy. Finally, the integrated model is compared with other existing erosion models. According to the comparative study, the non-optimized integrated model already owns the similar accuracy compared with existing erosion models, while the optimized integrated model performs best in accuracy and efficiency. Unlabelled Image • An integrated model is developed to predict sand erosion in elbows for multiphase flows. • Erosion coefficients are proposed to simplify models of different flow patterns. • The optimal coefficient shows advantages in improving the accuracy of prediction. • Maximum penetration ratio can be easily predicted with high accuracy. [ABSTRACT FROM AUTHOR]

Accurate prediction of soil detachment capacity is fundamental to establish process‐based erosion models and improve soil loss assessment. Few studies were conducted to reveal the mechanism of detachment process for yellow soil on steep cropland in the subtropical region of China using field experiments. This study was performed to determine soil detachment characteristics and explore the relationships between soil detachment capacity (Dc) and flow rate, slope gradient, mean velocity, shear stress, stream power and unit stream power. Field experiments were conducted on intact soil with flow rates ranging from 0.2 × 10−3 to 0.5 × 10−3 m−3 s−1 and slope gradients varying from 8.8 to 42.4%. The results showed the following. (a) Dc of yellow soil was smaller than other soils because of its high clay content. (b) Dc was more susceptible to flow than to slope gradient. Power functions were derived to depict the relationship between Dc and the flow rate and slope gradient (R2 = 0.91). (c) Dc was better simulated by power functions of the stream power (R2 = 0.83) than functions of the shear stress or the unit stream power. (d) Considering its accuracy, simplicity and accessibility, the power function based on flow rate and slope gradient is recommended to predict Dc of yellow soil in the field. The results of this study provide useful support for revealing soil detachment mechanism and developing process‐based soil erosion models for the subtropical region of China. [ABSTRACT FROM AUTHOR]

Soil erosion is sensitive to climate change, especially in high mountain areas. The Tibetan Plateau has experienced dramatic land surface environment changes under the impact of climate change during the last decades. In this study, we focused on the mid-Yarlung Tsangpo River (MYZ River) located in the southern part of the Tibetan Plateau. The revised universal soil loss equation (RUSLE) was applied to assess soil erosion risk. To increase its applicability to high mountain areas with longer periods of snowfall, snowmelt runoff erosivity was considered in addition to rainfall erosivity. Results revealed that soil erosion of the MYZ River region was of a moderate grade with an average soil erosion rate of 29.1 t ha−1 year−1 and most serious erosion in wet and cold years. Soil erosion rate in the MYZ River region showed a decreasing trend of − 1.14% year−1 due to the precipitation, temperature, and vegetation changes from 2001 to 2015, with decreasing precipitation being the most important factor. Increasing precipitation and temperature would lead to increasing soil erosion risk in ~ 2050 based on the Coupled Model Intercomparison Project (CMIP5) and RUSLE models. It is clear that soil erosion in high mountain areas greatly depends on climate state and attentions should be paid to address soil erosion problem in the future. [ABSTRACT FROM AUTHOR]

Erosion following human disturbance threatens ecosystem health and inhibits effective land use. Mountaintop removal/valley fill (MTR/VF) mined landscapes of the Appalachian Coalfields region, USA, provide a unique opportunity to quantify the geomorphic trajectory of disturbed lands. Here we assess how MTR/VF-induced changes to topography and vegetation influence spatiotemporal erosion patterns in five mined watersheds. We use landscape evolution models starting from pre- and post-MTR/VF topographic data to isolate the influence of mining-induced topographic change. We then constrain ranges of erodibility from incision depths of gully features on mine margins, and use those estimates to model the influence of vegetation recovery trends on erosion. Topographic alterations alone reduce total sediment export from mined catchments. Model runs that incorporate the disturbance and recovery of vegetation in mined watersheds show that complete vegetation recovery keeps millennial sediment export from mined catchments within the range of unmined catchments. If vegetation recovery is anything less than complete, vegetation disturbance drives greater total sediment export from mined catchments than unmined catchments. Full vegetation recovery causes sediment fluxes to decline over millennia beyond the recovery period, while watersheds without full recovery experience fluxes that increase over the same time period. Spatiotemporal erosion trends depend on 1) the extent of vegetation recovery and 2) the extent to which MTR/VF creates slope–area disequilibrium. Valley fills and mine scarps experience erosion rates several times higher than those found in the unmined landscapes. Rapid erosion of mined areas drives deposition in colluvial hollows, headwater stream valleys, and below scarps. Our experiments suggest that reclamation focused on maximizing vegetation recovery and reducing hotspots of slope–area disequilibrium would reduce MTR's influence on Appalachian watersheds both during and long after the vegetation recovery period. Insights from MTR/VF-influenced landscapes can inform mined land management as the renewable energy transition drives increased surface mining. [Display omitted] • We model 10,000 years of erosion beginning from both pre- and post-mining topography. • Mining-driven topographic changes alone reduce total erosion due to ridge flattening. • Incomplete vegetation recovery increases erosion in mined over unmined basins. • Erosion is focused in valley fills, deposition in low-order valleys and below scarps. • Vegetation recovery sets decadal sediment pulses and millennial landscape trajectory. [ABSTRACT FROM AUTHOR]

Surface mining may be humanity's most tangible impact on Earth's surface and will become more prevalent as the energy transition progresses. Prediction of post-mining landscape change can help mitigate environmental damage, but requires understanding how mining changes geomorphic processes and variables. Here we investigate surface mining's complex influence on surface processes in a case study of mountaintop removal/valley fill (MTR/VF) coal mining in the Appalachian Coalfields, USA. The future of MTR/VF landscapes is unclear because mining's effects on geomorphic processes are poorly understood. We use geospatial analysis—leveraging the existence of pre- and post-MTR/VF elevation models—and synthesis of literature to ask how MTR/VF alters topography, hydrology, and land-surface erodibility and how these changes could be incorporated into numerical models of post-MTR/VF landscape evolution. MTR/VF reduces slope and area–slope product, and rearranges drainage divides. Creation of closed depressions alters flow routing and casts doubt on the utility of models that assume steady flow. MTR/VF creates two contrasting hydrologic domains, one in which overland flow is generated efficiently due to a lack of infiltration capacity, and one in which waste rock deposits act as extensive subsurface reservoirs. This dichotomy creates localized hotspots of overland flow and erosion. Loss of forest cover probably reduces cohesion in near-surface soils for at least the timescale of vegetation recovery, while waste rock fills and minesoils also likely experience reduced erosion resistance. Our analysis suggests three necessary ingredients for numerical modeling of post-MTR/VF landscape change: 1) accurate routing and accumulation of unsteady overland flow and accompanying sediment across low-gradient, depression-rich, engineered landscapes, 2) separation of the landscape into cut, filled, and unmined regions, and 3) incorporation of vegetation recovery trajectories. Improved modeling of post-mining landscape evolution will mitigate environmental degradation from past mining and reduce the impacts of future mining that supports the energy transition. [Display omitted] • Mountaintop removal mining flattens topography and moves drainage divides. • Cut and filled domains generate different quantities of erosive runoff. • Creation of many closed depressions reduces applicability of common models. • Vegetation loss and material property changes increase erodibility. • Our work reveals the necessary elements for models of post-mining landscape change. [ABSTRACT FROM AUTHOR]

It is common knowledge that erosion depends on environmental factors modified by human activity. Erosion within a catchment area can be defined by local lithological, morphometric, hydrological features, etc., and land cover, with spatial distribution described by means of remote sensing tools. The study relied on spatial data for the catchment of the Lower Vistula—the biggest river in Poland. GIS (SAGA, QGIS) tools were used to designate the spatial distribution of independent environmental variables that determined the process of erosion according to land cover types within the Lower Vistula catchment (Corine Land Cover). In addition, soil loss in the catchment area was calculated using the USLE model (Universal Soil Loss Equation). The spatial data was used to determine the predictive power of variables for the process of erosion by applying the maximum entropy model (MaxEnt) commonly used in fields of science unrelated to fluvial hydrology. The results of the study pointed directly to environmental features strongly connected with the process of erosion, identifying areas susceptible to intensified erosion, and in addition positively verified by USLE. This testifies to the correct selection of the proposed method, which is a strong point of the presented study. The proposed interdisciplinary approach to predict erosion within the catchment area (MaxEnt), widely supported by GIS tools, will allow the identification of environmental pressures to support the decision-making process in erosion-prone areas.

The elbows are susceptible to the sand erosion during the transportation of oil and gas, especially for gas and annular flows. The objective of present work is to provide a simple and efficient method for predicting the sand erosion in elbows for both gas and annular flows. First, mechanistic analyses of the sand erosion in annular flow are conducted, and an erosion reduction coefficient is deduced to unify the erosion calculation in gas and annular flows. The erosion reduction coefficient is verified by a series of simulations with varying parameters, such as the superficial gas velocity, superficial liquid velocity, radius of curvature, pipe diameter, particle diameter and hardness of pipe wall. Then, the simulation results are employed to investigate the effects of second collision on the total erosion. Based on the investigation, two enhancement coefficients are proposed to estimate the contribution of second collision to the maximum penetration ratio and the most serious erosion position. Finally, by combining the above coefficients and the probability erosion models, a unified explicit correlation is derived for predicting the sand erosion in elbows and examined by the experimental data in gas and annular flows. The comparative study indicates that the new correlation performs well not only in simplifying the probability erosion models but also in predicting the maximum penetration ratio and the most serious erosion position. • A unified explicit correlation is proposed to predict sand erosion in elbows for gas and annular flows. • An erosion reduction coefficient in annular flow is deduced through mechanistic analyses. • Penetration enhancement coefficients are proposed to reflect the contribution of second collision to total erosion. • The correlation unifies and simplifies the probability models for gas and annular flows. • Maximum penetration ratio and most serious erosion position can be easily calculated without reducing accuracy. [ABSTRACT FROM AUTHOR]

In oil and gas industry, an increase in production is often achieved by injecting fracturing fluids with particles/proppants into rocks and reservoirs. There are various fracking fluids that oil and gas companies use, and some of these fracturing fluids demonstrate non-Newtonian flow behavior. In this paper, sand erosion behavior in shear-thinning carboxymethyl cellulose (CMC) solution is investigated with a jet impingement facility. Particularly, near wall flow speeds and particle impinging speeds are investigated in shear-thinning CMC fluids by Particle Image Velocimetery (PIV) and Particle Tracing Velocimetery (PTV) techniques. Computational Fluid Dynamics (CFD) are also used to predict the near wall particle impact information. The results indicate that different turbulence models resolve different near wall flow and particle impact characteristics. User Defined Functions (UDF) are developed and used to implement erosion ratio equations and simulate solid particle erosion behavior in the non-Newtonian fluid. The predictions are compared with experimental results. The results of this study can help improving erosion prediction in the hydraulic fracturing process utilizing CFD. • Erosion with shear-thinning CMC solution and sand particles are investigated with a jet impingement facility. • Cross constitutive model is implemented with CFD and is validated by PIV measurement. • Different turbulence models were conducted by predicting particle impact speeds and validated by PTV measurement. • Turbulence models are optimized to simulate erosion in non-Newtonian fluid and are comparison with erosion data. [ABSTRACT FROM AUTHOR]

Abstract Annular flow is a common flow pattern in oil and gas pipelines for its stability and efficiency. During the oil and gas production, sand particles are inevitably carried by annular flow to continuously impact on elbows, and thus make the sand erosion in elbows a notable problem. In the present work, both the first and second collisions are taken into account in the collision probability analysis. The decay effects of liquid film on particles are considered in calculating the impact velocities of particles, and the particle impact information is introduced into erosion correlations to estimate the erosion ratio. By combining the collision probability models and the erosion correlations, a novel probability model for annular flow is developed to predict the sand erosion in elbows. Numerous experiments are employed to examine the accuracy of the present model, and the applicability and efficiency of the probability model are demonstrated by comparing with other erosion models. Finally, the effects of first and second collisions on the formation of erosion profiles, as well as the relations between the erosion profile and the superficial gas velocity, superficial liquid velocity and curvature of elbow, are investigated in detail to acquire more knowledge of the sand erosion in elbows under annular flow conditions. Highlights • A probability model for annular flow is developed to predict the sand erosion in elbows. • Decay effects of liquid film on particle velocities are firstly introduced in theoretical analysis. • The erosion caused by second collision in annular flow is considered in analysis. • Maximum penetration rates and entire erosion profiles can be directly calculated. • The model shows advantages in both applicability and accuracy of prediction. [ABSTRACT FROM AUTHOR]

Abstract Erosion in hydraulic fracturing fluid is investigated utilizing Computational Fluid Dynamics (CFD) and with comparison to new experimental data for sand in shear thinning non-Newtonian fluids. A grid optimized CFD-based erosion prediction procedure is applied utilizing Dense Discrete Phase Model (DDPM) and one-way coupling model. The effect of different turbulence models on flow modeling, sand particle transport and impact characteristics are also examined. Constant viscosity fluid and power law constitutive equations are implemented and their capability in predicting erosion is examined by comparison to experimental data gathered in this investigation. This investigation has shown that significant error can arise from utilizing constant viscosity model to predict erosion resulting from particles entrained in non-Newtonian fluids. Thus, this investigation has resulted in selecting the best CFD approach and model combination for predicting erosion in this hydraulic fracturing non-Newtonian fluid. Highlights • Shear-thinning fluid rheology is implemented and flow field is simulated. • Dense Discrete Phase Model is applied and prediction results have been improved. • Near wall flow information and particle impact characteristics are investigated in detail to explain prediction results. • The best model combination to simulate erosion in non-Newtonian fluid is derived by comparison with erosion data. [ABSTRACT FROM AUTHOR]

One of the main factors affecting water erosion is rainfall erosivity. Knowledge of this factor can contribute to the prediction of soil losses and to the identification of the most suitable periods for agricultural cultivation operations. The use of software, based on current calculation tools, can contribute to the quick and accurate analysis of long series of rainfall data. The objective of this work is to determine the rainfall volume and rainfall erosivity (R), in different seasons of the year, through the correlation between the EI30 index, the rainfall coefficient (Rc) and the Fournier Index modified (MFI), for rainfall data from Pelotas-RS-Brazil. Rainfall data was used with an interval of 10 min, from 1993 to 2015, evaluated with the RainfallErosivityFactor package of the R-Project software. In the package, the R-factor is obtained by averaging the monthly EI30 values from the data series. Data was evaluated on a monthly, annual and seasonal scale. It was found that the average annual rainfall is 1369.46 mm, with February being the month with the highest rainfall. The series of annual precipitation data did not show a significant trend according to the Mann-Kendall test and the average annual erosivity is 8166.8 MJ mm h−1 ha−1 yr−1. Erosivity in summer is significantly higher than in winter, with the summer-autumn period accounting for 64.4% and winter represented only 17% of annual erosivity. There is a strong positive correlation between the erosivity and the rainfall coefficient, for monthly average data. Erosivity and MFI showed a very strong significant correlation for summer and autumn. The rainfall coefficient tended to show lower values in March and higher values in February. The results obtained are important to identify the periods of most critical erosivity, in which management systems must prioritize surface coverage and minimum soil disturbance. [Display omitted] • The month with the highest average monthly rainfall is February (153.0 mm). • November to February have the highest average erosivity. • The average annual erosivity for Pelotas-RS (1993–2015) is 8166.8 MJ mm h−1 ha−1 year−1. • The highest volumes of rain and the highest erosivity occur in the summer. • EI30 and MFI showed a very strong correlation for the summer/autumn period. [ABSTRACT FROM AUTHOR]

The aim of this research was to analyze erosion hazardous level (TBE) and predict the actual erosion (A) at Jatipurno Sub-District and planning of soil conservation when the actual erosion is more than the threshold at Jatipurno District. The USLE (Universal Soil Loss Equation) was used to predict actual erosion and erosion hazardous level then planning of soil conservation. The result showed that actual erosion level was varied from very light to heavy. The very light erosion, in range 0,2 ton/ha/yr to 7,8 ton/ha/yr the areas is about 1.879,19 ha (43,5%). The light erosion is 51,96 ton/ha/yr the areas is about 788,40 ha (18,3%). The moderate erosion is 92,83 ton/ha/yr the areas is about 694.95 ha (16,1%). The heavy erosion in range 209,84 ton/ha/yr to 377,21 ton/ha/yr the areas is about 952,80 ha (22,1%). Erosion hazardous level was varied from very light to very heavy. The very light erosion hazardous level covered areas of 1.034,77 ha (23,98%), the light erosion hazardous level covered areas 1.443 ha (33,44%), the heavy erosion hazardous level covered areas 1.204 ha (27,91%), the very heavy erosion hazardous level covered areas 632,88 ha (14,67%). Actual erosion dominated by very light level and TBE by the light level. Soil conservation planning is carried out by vegetative and mechanical conservation measures, such as planting variations of cover crops and terraces built in accordance with slope land and soil depths, land management according to local environmental and cultural preservation regulations and cooperation of all parties in environmental management can be done to prevent and minimize erosion.

The cavitating flow around a ship propeller was simulated with an implicit RANS based flow solver using the Volume of Fluid (VoF) method to model the interface between the two phases. The sliding interface method was applied to simulate the rotation of the propeller, comprising a rotor and a stator region. Erosion was predicted with a numerical model based on the microjet hypothesis, using the information from the flow solution. Simulations of a propeller under non-cavitating and cavitating conditions were compared to experimental measurements, thereby demonstrating the ability of the presented numerical method to qualitatively predict cavitation erosion for a ship propeller. [ABSTRACT FROM AUTHOR]

The transport of solids in multiphase flows is common practice in energy industries due to the unavoidable extraction of solids from oil and gas bearing reservoirs. The persistent collision of solids to the pipeline can lead to erosion, i.e., the removal of internal surface of the pipeline. Reliable estimates of erosion rates are essential for designing and safely operating pipelines that transport solids. Prediction of erosion rates in multiphase flow is a complex problem due to the lack of accurate models for predicting particle movements in the flow and their impact velocities to the wall. The erosion-rate calculations also depend on the accuracy of the flow regime predictions in the pipeline. The comparisons of existing model predictions to experimental data revealed that the predictions might differ by several orders of magnitude for some operating conditions. The goal of this paper is to introduce a computational framework that estimates the model-prediction uncertainty of erosion-rate models. The inputs are a model predicting erosion rates and a database containing erosion-rate measurements at various operating conditions. The framework utilizes a non-parametric regression analysis, Gaussian Process Modeling (GPM), for estimating the model-prediction uncertainty. We compare two approaches for clustering the data prior to training GPMs: (1) a flow regime based clustering, and (2) a new clustering approach introduced in this paper. The results reveal that the new data clustering approach significantly shrinks the confidence intervals of the uncertainty estimates. [ABSTRACT FROM AUTHOR]

Erosion caused by particles transported in pipes is a major concern in industrial processes. To describe the erosion behavior in elbows, the flow field, particle trajectories, and relationship between the maximum erosion zone and influencing factors were investigated by using computational fluid dynamics (CFD). The accuracy of the presented method was verified by experimental data available in the literature. Good agreement between the predictions and experimental data was observed. Furthermore, the particle diameter, pipe geometry parameters, and operating conditions in pipeline transportation were analyzed to determine the maximum erosion zone. The results show that (1) the Stokes number for particle motion in the elbow has a certain effect as the particles move with the eddy but has no decisive influence on the location of the maximum erosion zone; (2) the erosion zone is directly related to the particle diameter; and (3) increasing the radius of curvature will change the flow field in the pipe and, in turn, the location of the maximum erosion zone. [ABSTRACT FROM AUTHOR]

Sand erosion is a common problem in oil and gas industry, which may lead to unpredictable failure and economic loss of pipeline systems. Due to the relatively stable state, annular flow is the predominant flow pattern and can simultaneously transport two kinds of materials (such as liquid and gas), which can reduce expenses for oil and gas production. In the present work, an accurate combination of the correlations of entrainment fraction and liquid film thickness is introduced into a modified numerical model, and is validated by experimental data. A series of numerical simulations are designed and performed to investigate the coupling effects of different parameters on erosion, such as the liquid dynamic viscosity, pipe diameter, superficial gas velocity, radius of curvature, superficial liquid velocity and particle size. Based on the knowledge gained from numerical analysis, the dimensionless π groups are proposed as well as a correlation for predicting sand erosion in annular flow, which takes the effect of liquid dynamic viscosity into account. By comparing with the experimental data and other existing correlations, the proposed correlation is confirmed as an effective and concise method, and shows good accuracy in erosion prediction. [ABSTRACT FROM AUTHOR]

At the Institute of Thermal Turbomachinery and Machinery Laboratory (ITSM) Stuttgart, the droplet impact erosion phenomenon has been simulated with the help of an erosion test rig. The experiments confirm that the erosion resistance of steam turbine blade materials can be associated with different mechanical properties of materials. Different combinations of material properties, like hardness, yield strength, Young's modulus and resilience, are analysed and their role in the formation of material erosion resistance is investigated. These material properties are, later on, used to predict the erosion behaviour of blade materials in a given erosive environment. In the end, an empirical erosion prediction model is presented and described. With the help of this erosion model, the rig-specific erosion resistance of a candidate blade material can be predicted if its material properties are known. [ABSTRACT FROM AUTHOR]

Erosion damage is one of the main factors leading to failure of pipeline in oil field, especially for sudden contraction section under solid-liquid two-phase flow in hydraulic fracturing. In this article, a laboratory experiment was carried out to analyze the effects of pipe flow velocity, particle concentration and pipe inner diameter ratio on particle erosion of the reducing wall in high-viscosity liquid. The results show that the erosion rate and erosion distribution are different not only in radial direction but also in circumferential direction of the sample. The upper part of sample always has a minimum erosion rate and erosion area. Besides, the erosion rate of reducing wall is most affected by fluid flow velocity, and the erosion area is most sensitive to the change in the diameter ratio. Meanwhile, the erosion rate of reducing wall in cross-linked fracturing fluid is mainly determined by the fluid flowing state due to the high viscosity of the liquid. In general, the increase in flow velocity and diameter ratio not only causes the expansion of erosion-affected flow region in sudden contraction section, but also leads to more particles impact the wall. [ABSTRACT FROM AUTHOR]

Abstract: Soil erosion is a serious problem world‐wide for the environment or humankind, exacerbating land degradation. However, little systematic knowledge is available about the erodibility of various types of soils at different erosional degradation levels, especially at the field scale. In this research, the spatiotemporal variations of the erodibility for 5 soil types (calcic luvisol, ferric luvisol, plinthic alisol, plinthic acrisol, and acric ferralsol) from temperate to tropical climate were investigated with field rainfall simulation experiments on prewetted bare fallow heavy‐textured soils (silty clay loam, silty clay, and clay) derived separately from loess deposits, quaternary red clays, and basalt. The experiments were performed in 3 erosion classes (noneroded, moderately eroded, and very severely eroded) and at 2 rainfall intensities (45 and 90 mm hr−1). Soil erodibility was represented by the K factor of the Revised Universal Soil Loss Equation. Soil erodibility was the lowest for the ferralsols among all the soil types and was significantly lower in the very severe than in the no or moderate erosion classes. Soil erodibility tended to be larger at the high than at the low rainfall intensity (p < .05) except for the very severely eroded luvisols, and their difference between rainfall intensities in the erodibility varied with rainfall duration. Soil erodibility could be well predicted by the combination of illite, dry aggregate stability, and amorphous aluminium oxides (adjusted R2 = .51, p < .001), and its temporal variations were significantly related with particle density, 1.4‐nm intergrade mineral, and capillary porosity (p < .05). Furthermore, soil properties selected to account for soil erodibility varied with rainfall intensity. The integrated data indicated that soil erodibility was mainly influenced by clay minerals at the region scale and soil degradation degree at the pedon scale. [ABSTRACT FROM AUTHOR]

Soil erosion by water is one of the main soil degradation processes worldwide, which leads to declines in natural soil fertility and productivity especially on arable land. Despite advances in soil erosion modelling, the effects of compacted tramlines are usually not considered. However, tramlines noticeably contribute to the amount of soil eroded inside a field. To quantify these effects we incorporated high-resolution spatial tramline data into modelling. For simulation, the process-based soil erosion model EROSION3D has been applied on different fields for a single rainfall event. To find a reasonable balance between computing time and prediction quality, different grid cell sizes (5, 1, and 0.5 m) were used and modelling results were compared against measured soil loss. We found that (i) grid-based models like E3D are able to integrate tramlines, (ii) the share of measured erosion between tramline and cultivated areas fits well with measurements for resolution ≤1 m, (iii) tramline erosion showed a high dependency to the slope angle and (iv) soil loss and runoff are generated quicker within tramlines during the event. The results indicate that the integration of tramlines in soil erosion modelling improves the spatial prediction accuracy, and therefore, can be important for soil conservation planning.

The Bank Assessment of Nonpoint source Consequences of Sediment ( BANCS) framework allows river scientists to predict annual sediment yield from eroding streambanks within a hydrophysiographic region. BANCS involves field data collection and the calibration of an empirical model incorporating a bank erodibility hazard index ( BEHI) and near-bank shear stress ( NBS) estimate. Here we evaluate the applicability of BANCS to the northern Gulf of Mexico coastal plain, a region that has not been previously studied in this context. Erosion rates averaged over two years expressed the highest variability of any existing BANCS study. As a result, four standard BANCS models did not yield statistically significant correlations to measured erosion rates. Modifications to two widely used NBS estimates improved their correlations ( r2 = 0.31 and r2 = 0.33), but further grouping of the data by BEHI weakened these correlations. The high variability in measured erosion rates is partly due to the regional hydrologic and climatic characteristics of the Gulf coastal plains, which include large, infrequent precipitation events. Other sources of variability include variations in bank vegetation and the complex hydro- and morphodynamics of meandering, sand bed channels. We discuss directions for future research in developing a streambank erosion model for this and similar regions. [ABSTRACT FROM AUTHOR]

Soil erosion from cropland is a primary cause of soil degradation in the hilly red soil region of China. Soil characteristics and the resistance of soil to erosion agents can be improved with appropriate management practices. In this study, hydraulic flume experiments were conducted to investigate the effects of five management practices [manure fertilizer (PM), straw mulch cover (PC), peanut-orange intercropping (PO), peanut-radish rotation (PR) and traditional farrow peanut (PF)] on soil detachment. Based on the results, three conservation management practices (PC, PM and PO) increased the resistance of soil to concentrated flow erosion. The rill erodibility of different treatments was ranked as follows: PC (0·001 s m−1) < PM (0·004 s m−1) < PO (0·007 s m−1) < PF (0·01 s m−1) < PR (0·027 s m−1). The rill erodibility was affected by soil organic content, aggregate stability and bulk density. The soil detachment rate was closely correlated with the flow discharge and slope gradient, and power functions for these two factors were developed to evaluate soil detachment rates. Additionally, the shear stress, stream power and unit stream power were compared when estimating the soil detachment rate. The power functions of stream power and shear stress were equivalent, and both are recommended to predict detachment rates. Local soil conservation can benefit from the results of this study with improved predictions of erosion on croplands in the red soil region of China. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In the field of petrochemical industry, the pipe bend of pipeline transportation system is very vulnerable to the sand particle erosion. In this paper, the influence of fluid factor, solid particle factor and pipe size factor on the sand erosion rate of two-phase flow pipe bend is studied by using the fluid computational dynamics (CFD) method. The influence degree of different factors on the erosion rate and the prediction models of the maximum erosion rate are obtained by using grey correlation analysis and data fitting method. The comparison between the experimental data and the prediction models shows that the prediction results agree well with the experimental data. Furthermore, the two-phase flow erosion rate prediction models are applied to the gas-liquid-solid multiphase flow erosion conditions, and their prediction accuracy and adaptability are analyzed. This study can provide ideas and prediction methods for sand erosion prediction in gas-liquid-solid multiphase flow pipeline. The erosion prediction model agrees well with the experiment data. [Display omitted] • Two-way coupling method was employed in two-phase flow erosion simulation. • The influence of different erosion factors on pipe bend erosion was ranked. • The erosion prediction models of gas-solid flow and liquid-solid flow are established. • Two-phase flow erosion prediction models were applied and evaluated in gas-liquid-solid multiphase flow erosion conditions. [ABSTRACT FROM AUTHOR]

Soil erosion prediction technology began over 70 years ago when Austin Zingg published a relationship between soil erosion (by water) and land slope and length, followed shortly by a relationship by Dwight Smith that expanded this equation to include conservation practices. But, it was nearly 20 years before this work's expansion resulted in the Universal Soil Loss Equation (USLE), perhaps the foremost achievement in soil erosion prediction in the last century. The USLE has increased in application and complexity, and its usefulness and limitations have led to the development of additional technologies and new science in soil erosion research and prediction. Main among these new technologies is the Water Erosion Prediction Project (WEPP) model, which has helped to overcome many of the shortcomings of the USLE, and increased the scale over which erosion by water can be predicted. Areas of application of erosion prediction include almost all land types: urban, rural, cropland, forests, rangeland, and construction sites. Specialty applications of WEPP include prediction of radioactive material movement with soils at a superfund cleanup site, and near real-time daily estimation of soil erosion for the entire state of Iowa.