Erosion Prediction Research Articles

Dual role of microparticles in synergistic cavitation–particle erosion: Modeling and experiments

The synergy between cavitation erosion and solid particle erosion fascinates tribologists owing to the contradicting roles of microparticles in aggravating or alleviating erosion. Based on an effective-medium approach, we develop a theoretical model to predict synergistic erosion, which incorporates the influence of suspension viscosity on bubble/particle dynamics and the impact energy of erosive particles. The model was experimentally validated, with strong agreement between the model predictions and experimental results. Further analysis shows that the viscous effect of silt-sized particles (STPs, <50 μm) could mitigate or even override the impact of impinging micro-jets and sand-sized particles (SDPs, >50 μm). The critical sand-to-silt ratio—the SDP/STP ratio that results in the same material removal as that in the solids-free case—is found to be a key parameter in the prediction of the synergistic erosion. The model embodies the opposing effects of microparticles on the cavitation erosion, and shows promise for erosion prediction and prevention.

Establishment of PM10 and PM2.5 emission inventories from wind erosion source and simulation of its environmental impact based on WEPS-Models3 in southern Xinjiang, China

Southern Xinjiang located in the far northwest of China is experiencing serious particulate matter (PM) pollution. The wind erosion has been recognized as a great contributor of PM10 and PM2.5 concentrations in southern Xinjiang. In this study we developed a method that used the Wind Erosion Prediction System (WEPS) to establish the PM10 and PM2.5 emission inventories from the wind erosion source in southern Xinjiang with a 10 km × 10 km spatial resolution and a temporal resolution of one month. The PM10 and PM2.5 emission inventories from wind erosion sources were provided as input to the Models3/SMOKE (Sparse Matrix Operator Kernel Emission). The Community Multi-scale Air Quality (CMAQ) model was employed to simulate PM10 and PM2.5 concentrations from wind erosion source and the results were compared with the monitoring data to verify the emission inventories. The total PM10 and PM2.5 emissions were 12 × 106 t and 4 × 106 t, respectively, and the emission per unit area were 14.6 t/km2 and 4.9 t/km2, respectively, in southern Xinjiang in 2016. The PM10 and PM2.5 emissions per unit area were highest in Kashi being 19.1 t/km2 and 9.1 t/km2, respectively. The total emissions peaked at 5.4 × 106 t/km2 in PM10 and 1.4 × 106 t/km2 in PM2.5 in Bazhou. The PM10 and PM2.5 emissions were highest in spring, followed by summer, winter and autumn. The Normalized Mean Error (NME) between the predicted monthly average PM10 and PM2.5 concentrations from wind erosion source and the results from multiplying the monitoring data by the source apportionment results of PM10 and PM2.5 were 25.3% and 26.1%, respectively, which indicated that the accuracies of the PM10 and PM2.5 emission inventories from wind erosion source in southern Xinjiang were satisfactory.

Erosion Control and Growth Promotion of W-OH Material on Red Clay Highway Slopes: A Case Study in South China

Ecological restoration is difficult on the red clay highway slopes in the rainy areas in South China that experience severe soil erosion. By using the hydrophilic polyurethane material W-OH to solidify and protect red clay slopes, the erosion control will be substantially improved. We employed simulated rainfall erosion experiments and pot experiments to evaluate the anti-corrosion and growth promotion performances. We found that, (1) in the initial stage of protection, W-OH had the effect of accelerating slope drainage, solidifying the soil structure, and reducing soil loss, with the sediment reduction benefit reaching 37.4–65.3%. (2) The anti-erosion effect was mainly based on soil solidification. (3) The W-OH was affected by rainfall intensity and the W-OH concentration, and the soil erosion prediction equation was constructed according to the observation. (4) W-OH had a promising water retention performance and can promote the germination and late growth of slope plants to reduce the influence of eluviation. (5) The suitable W-OH solution concentration was 3–5% for slope protection herbs and shrubs, which were commonly used in South China. (6) The reduction in porosity was the fundamental cause of water retention improvement. The ecological restoration of slopes is a comprehensive process. Therefore, both anti-erosion performance and later plant growth are necessary. Our research provides a theoretical and experimental basis for applying the W-OH in the ecological restoration of the red clay slopes in subtropical areas and expanding the scope of the W-OH.

A localized sand erosion prediction approach for multiphase flow in wells: application for sudden-expansions

The present study aims at finding the severity of the erosional damage for sudden-expansion geometries in a candidate oil well. A two-step approach is proposed for the localized erosion prediction in wells. At first, one-dimensional flow through the well strings is solved using the transient multiphase flow simulator, OLGA, which provides phase properties and flow conditions for the local erosion calculation. Then, the recorded flow data are employed for a detailed three-dimensional computational fluid dynamics (CFD)-based flow and erosion calculation in the selected sections of the well. In this study, two sudden-expansion geometries at substantially different depths are selected and investigated. Erosion magnitude and its pattern are evaluated for multiphase flow conditions and compared with single-phase flow. It is found that the erosional damage for the multiphase flow could be because of the random impingements due to the pipe size effect on the multiphase flow regime which is an indirect effect of the flow transition through sudden-expansion. The most severe condition is encountered for the expansion geometry closer to the wellhead, but the annual erosion rate is below the critical rate. However, for the dry-gas wells when a liquid film is not present, the erosion rate could be significantly above the critical rate.

Effect of distance between two elbows in series on erosion for gas dominated conditions

Solid particle erosion is a potential problem in pipelines for the oil and gas processing industries. Solid particle erosion usually occurs in piping components or equipment when the direction of the flow changes, such as in elbows and tees. The distance between two elbows effects on the behavior of solid particle erosion on the second elbow has been investigated experimentally and computationally. Firstly, paint removal experiments were carried out to investigate the erosion pattern in a standard 3-inch (76.2 mm) elbow with a bend radius to pipe diameter (r/D) ratio equal to 1.5 for a gas-sand condition with different particle sizes. The investigated distances between the two elbows are 2D and 12D. Secondly, the erosion magnitudes in a standard 3-inch (76.2 mm) stainless steel elbow were measured using a state-of-the-art ultrasonic technique. These results have been compared with the previous experimental data in a 4-inch (101.6 mm) elbows to investigate the pipe size effect. Thirdly, a commercial CFD code was used to simulate the experimental conditions and compare erosion predictions with the experimental results. Different turbulence and particle rebound models were applied in the CFD simulations to examine their influence on the predicted erosion on the elbows. Finally, the effect of distance between the two elbows on the particle trajectories were investigated using the CFD approach.

Experimental and Numerical Evaluation of the Effect of Particle Size on Slurry Erosion Prediction

AbstractDuring petroleum production, sand particles can be entrained with the transported carrier fluid despite of any sand exclusion process and erode the inner walls of the pipelines. This erosion process may even cause pipe leakage and oil spill. Therefore, investigating the regularities of erosion damage changing with particle size and predicting erosion behavior for different particle sizes are important to pipeline safety. In this study, slurry erosion experiments are conducted using quartz particles with similar shapes and different sizes ranging from 25 μm to 600 μm to investigate the effect of particle size on erosion profiles and provide the database for evaluating available erosion models. Computational fluid dynamics (CFD) is used to simulate the fluid flow and track particles to obtain impact information. Erosion equations then connect the particles’ impact information with erosion rate. Finally, the available mechanistic and empirical equations erosion models are evaluated by comparing predicted erosion profile with experimental data. It was found that the local maximum erosion damage increases with particle size, although the total erosion ratio is not changing significantly. These changes of erosion profiles can be predicted with acceptable accuracy by available empirical erosion models when particle sizes are no less than 75 μm.

Sediment fate and transport: Influence of sediment source and rainfall

The capability of hydrologic models to spatially simulate the changes in hydrologic processes, like precipitation, is an important consideration in capturing the impacts of these processes on sediment prediction across the domain. Radar-derived precipitation (RDP) provides an enhanced detail of rainfall characteristics in time and space compared to estimates from rain-gauge precipitation (RGP) commonly used in hydrologic modeling. However, the impacts of these datasets on sediment fate and transport depend on how sediment sources were conceptualized in the model. This paper developed a modeling framework to simulate sediment transport from upland to the stream and to the outlet of the watershed based on a gridded conceptualization and to examine the impacts of RGP and RDP with different types of sediment sources on sediment prediction. The Water Erosion Prediction Project (WEPP) model was used to estimate daily sediment sources in a semi-distributed and fully distributed manner using the hydrologic model, MIKE SHE and MIKE 11. Model comparison was performed in a watershed in Illinois characterized by a dominant agricultural landscape. The results indicated that the use of RDP only ensured better model performance for sediment yield with the fully distributed sediment source. That is, combining both the ability of the RDP to capture the spatial variability of rainfall across the watershed and assessing sediment production at higher resolution improved the accuracy of predictions in sediment yield while decreasing uncertainties associated with sediment simulations. Advancing modeling capabilities will require the development of new modeling platforms that aim to seamlessly integrate large-scale distributed simulations and environmental input data at finer spatial resolutions.

Performance prediction of erosion in elbows for slurry flow under high internal pressure

Slurry erosion is an important cause of material failure in the oil and gas industry. Particularly, during hydraulic fracturing, the fracturing pipelines under high internal pressure inevitably suffer from erosion wear. In this study, the erosion tests involving tensile stress were carried out and a new stress-erosion model suitable for high internal pressure was developed based on the experimental data. Then the established erosion model was applied to conduct the numerical simulation to investigate the erosion behaviour in elbows of fracturing pipeline under different conditions. Finally, an intelligent method of erosion prediction was explored using machine learning technology, providing a potential solution in predicting the erosion severity of elbows under high internal pressure.

Agricultural erosion modelling: Evaluating USLE and WEPP field-scale erosion estimates using UAV time-series data

Soil erosion models, typically applied at basin and watershed scales, are rarely evaluated at agricultural field scales due to the lack of spatially-distributed time series data. A novel unmanned aerial vehicle (UAV) methodology was used to quantify farm-field soil erosion from nine UAV surveys and structure-from-motion (SfM). Using a semi-distributed approach, we evaluated soil erosion estimates from the Universal Soil Loss Equation (USLE) and Water Erosion Prediction Project (WEPP). The annual erosion rate, measured with the UAV methodology, was 18.83 t ha−1 yr−1, with USLE and WEPP predictions of 26.23 t ha−1 yr−1 and 16.41 t ha−1 yr−1, respectively. Modelled annual and sub-annual erosion rates with WEPP were within the upper-limit of predictive accuracy, while the USLE tended to systematically overestimate soil erosion rates. These outcomes have implications on the efficacy of conservation efforts, which is highlighted through a discussion and comparison of different best-management practice applications.

An improved vegetation cover and management factor for RUSLE model in prediction of soil erosion.

Soil erosion and runoff of cultivated land will cause farmland to be degraded and the downstream to be contaminated, which has aroused extensive attention worldwide. The conventional soil loss prediction model revised universal soil loss equation (RUSLE) is capable of more significantly simulating and predicting the amount of soil loss, but this model often cannot achieve the satisfied prediction accuracy when the rainfall distribution of 1year is significantly inconsistent with the annual distribution law. In this study, the 3-year field experiments were performed in Jilin, China. Besides, an improved revised universal soil loss equation (IRUSLE) was provided with a novel vegetation cover and management factor (C). It considered the interaction between rainfall distribution and normalized difference vegetation index (NDVI) by theoretical analysis and the genetic algorithm. It was reported that IRUSLE model can achieve more effective simulation result than RULSE model, as well as laying a theoretical basis for soil loss prediction.

Numerical prediction of sediment erosion in reference Francis turbine for complete operating range

Erosive and abrasive wear affect the overall performance of hydro-turbines. Hard and excessive sediment particles are unavoidable in power plants of Himalayan basins. However, modifying the design of turbine components to have a minimum impact of the sediments could be one of the viable solutions. Past studies have shown possibilities of minimizing the erosion in turbine components by changing the blade angle distribution of the runner. The optimizations were based on the designed condition, i.e. at the Best Efficiency Point (BEP) of the turbine. The turbines are however, operated in various conditions, which might produce a different erosion scenario compared to BEP. Hence, the optimization process should also take these off-designed points under consideration. This paper presents a case study of Jhimruk hydropower plant of Nepal, whose turbine components get severely eroded due to sediments. Steady state numerical simulations for 4 guide vanes and 3 runner blade passages are done for the predictions of efficiency and percentile sediment erosion rate density (PSERD) on runner blades for 11 operating conditions including BEP. Apart from the conventional efficiency hill chart diagram, this paper focuses on the development of a hill diagram of PSERD, such that the prediction of the erosion in turbines can be done similar to the efficiency. Introduction of such PSERD hill diagrams could be a standard mean for the design optimization of turbines in sediment laden water.

Temporally downscaling precipitation intensity factors for Köppen climate regions in the United States

Model inputs for prediction of runoff and soil erosion commonly require precipitation intensity information. Intensity is often estimated if precipitation data with high temporal resolution are unavailable. However, when intensity is time-averaged for fixed measurement intervals, estimates become increasingly underestimated with longer intervals due to the assumption that event durations begin and end at specified measurement intervals. In this study, adjustment factors were determined for downscaling the temporal resolution of intensity values derived from selected resolutions within the range of 10 to 1,440 min for Köppen-Geiger climate regions in the United States. In this case, monthly mean maximum 30 min intensity (MX.5P) was downscaled, which is a parameter used to generate stochastic meteorological inputs for models that include the Rangeland Hydrology and Erosion Model (RHEM) and the Water Erosion Prediction Project model (WEPP). The adjustment factors were given by regressions of reference MX.5P values derived from data with 5 min resolution against MX.5P values derived from data with lower temporal resolutions (≥10 min). In addition to using a slope coefficient for intensity in the regression equation, permutations of the equation included use of an elevation coefficient and constants, resulting in four total permutations. For the 143 stations and 17 climate regions analyzed, the four regression equations had roughly equal performance, and all gave statistically significant results. Regressions for adjusting hourly data using only an intensity coefficient in the equation had standard error of the estimate ranging from 1.01 to 2.96 mm h^–1 with an average of 2.04 mm h^–1. When downscaling daily values, the error range was 2.50 to 10.20 mm h^–1 with an average of 5.63 mm h^–1. Average time-to-peak intensity probability distributions for each climate region were also determined. Finally, a stochastic weather generator, CLIGEN, was used to test the effectiveness of applying the climate-based factors as an alternative to using subhourly data.

Verification of CFD Prediction Accuracy of Particle and Droplet Induced Erosion Rate for Engineering Applications

The solid particles or liquid droplets entrained by multi-phase flow in process plants can cause erosion resulting in pipe wall thinning. Hence, it is essential to evaluate erosion rate for determining design margin and taking counter-measures. Many models have been proposed for prediction of erosion induced by particles and droplets, but there is significant difference in their prediction accuracy. The present study aims at verifying prediction accuracy of some major erosion models using the published experimental data, for engineering applications. CFD benchmark simulations were conducted for different flow velocities and piping geometries to investigate prediction accuracy of particle-induced erosion rates for five major erosion models, using the experimental data in literature. CFD results show that the erosion rates predicted by Grant and Tabakoff model are closest to the experimental results with acceptable prediction accuracy for engineering applications. At the same time, CFD benchmark simulations were also carried out to verify the prediction accuracy of droplet induced erosion rates for three erosion models, using the published experimental data. CFD results show that the erosion rates predicted by Haugen model for all the water impingement velocities are closest to the experimental results with acceptable prediction accuracy for engineering applications.

Geographic information system and process-based modeling of soil erosion and sediment yield in agricultural watershed

BACKGROUND AND OBJECTIVES: The study explored the capability of the geographic information system interface for the water erosion prediction project, a process-based model, to predict and visualize the specific location of soil erosion and sediment yield from the agricultural watershed of Taganibong.METHODS: The method involved the preparation of the four input files corresponding to climate, slope, land management, and soil properties. Climate file processing was through the use of a breakpoint climate data generator. The team had calibrated and validated the model using the observed data from the three monitoring sites.FINDINGS: Model evaluation showed a statistically acceptable performance with coefficient of determination values of 0.64 (probability value = 0.042), 0.85 (probability value = 0.000), and 0.69 (probability value = 0.001) at 95% level, for monitoring sites 1, 2, and 3, respectively. A further test revealed a statistically satisfactory model performance with root mean square error-observations standard deviation ratio, Nash-Sutcliffe efficiency, and percent bias of 0.62, 0.61, and 44.30, respectively, for monitoring site 1; 0.65, 0.56, and 25.60, respectively, for monitoring site 2; and 0.60, 0.65, and 27.90, respectively, for monitoring site 3. At a watershed scale, the model predicted the erosion and sediment yield at 89 tons per hectare per year and 22 tons per hectare per year, respectively, which are far beyond the erosion tolerance of 10 tons per hectare per year. The sediment delivery ratio of 0.20 accounts for a total of 126,390 tons of sediments that accumulated downstream in a year.CONCLUSION: The model generated maps that visualize a site-specific hillslope, which is the source of erosion and sedimentation. The study enables the researchers to provide information helpful in the formulation of a sound policy statement for sustainable soil management in the agricultural watershed of Taganibong.

Rainfall Erosion Predictions for Artificial High‐Filled Embankment with Reinforcement

In recent years, rainstorm disasters caused by global warming have frequently occurred in China. It has caused serious damage to artificial high embankments. In this paper, the influence of rainfall intensity, slope, and reinforced layers on the erosion and destruction of the artificial high embankment is deeply analyzed. Through the model test, the rainfall erosion prediction model is established. The results show that (1) the gully width, depth, and erosion amount increased with the increase in rainfall intensity and slope and decreased with the increase in reinforcement layers; (2) the final ditch shape of the embankment is influenced by steel bars; and (3) according to the model test data, the mathematical model of dike scouring is established. Rainfall intensity and the coupling between slope and reinforced layers are considered in the model. It can be used for predicting erosion during rainfall.

Spatiotemporal variation of erosive rainfall and its influence on sediment discharge in the Ganjiang River Basin

Expected increases in extreme rainfall events due to global warming could lead to increased soil erosion in mountainous areas. In order to study this impact on specific areas, the present study identified the spatiotemporal variation of erosive rainfall and the influence of its variation on streamflow and sediment discharge within the Ganjiang River Basin. Daily average rainfall data were obtained from 23 national meteorological observation stations along with streamflow and sediment concentration data collected for 1964-2013 at 6 control stations. The nonparametric Mann-Kendall method and Pettitt test were used for trend analysis and change-point detection, and the modified double mass curve method was used to quantify the effects of both erosive rainfall variation and human activities on hydrological regime shifts. Results showed significant monthly variation in erosive rainfall and significant increases in rainstorms over the entire watershed, particularly in the downstream subzone and northeast corner of the upstream subzone. While moderate rain showed an insignificant decrease in both subzones and the entire watershed, heavy rain showed no significant variation over the entire watershed but did show a significant increase in both the midstream and downstream subzones. The changes in accumulative erosive rainfall had only small effects on reduction in sediment discharge after the change-point year. In contrast, human activities contributed to more than 50% of the changes in sediment discharge in the entire basin. These findings provide a research basis for the study of extreme climate, flood disaster prevention, and soil erosion prediction over the entire watershed.

PRESSURE DROP ANALYSIS AND EROSION PREDICTION FOR THE FLOW OF A MULTI-SIZE PARTICULATE SLURRY ACROSS A HORIZONTAL PIPE

PRESSURE DROP ANALYSIS AND EROSION PREDICTION FOR THE FLOW OF A MULTI-SIZE PARTICULATE SLURRY ACROSS A HORIZONTAL PIPE

Comparison of the erosion prediction models– A case study of coastal region

Water erosion is one of the most serious problems of soil degradation in the world, the Konkan region of Maharashtra state is particularly exposed to this phenomenon. In recent times, the estimation of soil erosion using empirical models has been a promising research topic as their application over a large and ungauged areas remains a real challenge due to the limited availability and quality of the required data. Using the geospatial technologies, this study aims to estimate and compare the soil erosion rates by the two models of Universal Soil Loss Equation (USLE) and Modiûed Universal Soil Loss Equation (MUSLE) for Ratnagiri district in Konkan region of India. Soil loss of Ratnagiri district by USLE model was found to be43.61 t/ha/yrand sediment yield by MUSLE model was 33.45 t/ha/yr. Sediment yield was more than 70% of total soil loss, which is on higher side by 20% for Konkan region but follows the runoff percentage trend. So, MUSLE model can be used with caution of overestimation in data scare situation in heavy rainfall, hilly region of lateritic soil, wherever runoff gauging stations are not available.

USE OF REMOTE SENSING TECHNIQUES AND NUMERICAL MODELLING TO PREDICT COASTAL EROSION IN VIETNAM

Accurate prediction of coastal erosion is of importance for the investment planning of measures enhancing resilience to natural hazards. Field data on historical is generally lacking. Recent advances in deriving historical shoreline position from freely available satellite images combined with numerical modelling of shoreline erosion provide a reliable method for prediction of coastal erosion. This paper discusses the available tools and presents their application in a study case in Quang Ngai City, Vietnam.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/oOk9-bmDorA

QUANTIFYING THE INFLUENCE OF TRANSITIONS ON GRASS COVER EROSION BY OVERTOPPING WAVES

Transitions in vegetated dike covers, such as geometry changes or roughness differences, are identified as weak spots in dikes for grass cover erosion by wave overtopping. Although several erosion models exist to model grass cover erosion on dikes, it is unclear how the effect of transitions on grass cover erosion must be included in these models. Therefore, we have developed a model approach to analyze the effects of transitions on grass cover erosion using field experimental data and to derive representative influence factors for one transition type. The model approach has been applied to the transition at the landward toe where the slope changes to a horizontal plane. The model approach is general applicable and can be transferred easily to other transitions. The derived factors can be used to improve predictions of dike cover erosion near transitions.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/YVH6PN4-Er0