2D axisymmetrical numerical modelling of the erosion of a cohesive soil by a submerged turbulent impinging jet

Abstract

International audienceThis study focuses on 2D Computational Fluid Dynamics (CFD) numerical modelling of the erosion of a cohesive soil by a circular impinging turbulent jet. Initially, the model is validated in the case of a non erodible flat plate. Several turbulence models are compared to experimental results and to simplified formulas available in the literature. The results obtained show that the Reynolds Stress Model (RSM) is in good agreement with the semi-empirical results in the literature. Nonetheless, the RSM cannot be used with successive remeshings, due to its convergence issues. The shear stress at the wall is well-described by the k-ε model while the pressure is better-described by the k-ω model. The numerical model of erosion is based on adaptive remeshing of the water/soil interface to ensure the good precision of the mechanical values at the wall. The two erosion parameters are the critical shear stress and the erosion coefficient. The results obtained are compared with the semi-empirical model interpreting the Jet Erosion Test. The k-ε model underestimates the shear stress and does not allow simulation of the entire erosion process, whereas the results obtained with the k-ω model agree well with the semi-empirical model and experimental data. A study of the influence of erosion parameters on erosion kinetics and scouring depth shows that the shape and depth of scouring are influenced solely by the critical shear stress while the duration of scouring depends on both erosion parameters. Further research is nonetheless required to better understand the erosion mechanisms in the stagnation zone

Erosion threshold of a liquid immersed granular bed by an impinging plane liquid jet

“…This detailed study of the erosion threshold with the jet structure may be useful for a better understanding of the subsequent cratering beyond threshold where the shape modification of the surface affects the impingement flow structure, and could help for the validation of new numerical methods. 28,42 …”

The influence of impinging distance variable on the effect of submerged jet scour

“…To simplify the calculation process, this study focuses on the influence of impinging distance on the sand pit contour from a two-dimensional perspective, thereby reducing the computational workload [7][8][9]. The geometric model, as shown in Figure 1, consists of a tank measuring 0.9 m × 0.5 m, with a deposited sand height of 0.2 m. The nozzle, placed at the center of the model, has a diameter (D) of 3 mm, and the initial water level height (Z) is set at 0.5 m. The simulation duration is 20 seconds.…”

Perspective: Lessons Learned, Challenges, and Opportunities in Quantifying Cohesive Soil Erodibility with the Jet Erosion Test (JET)

“…Initial efforts combined CFD simulations for solving the JET hydrodynamics with erosion laws and adaptive remeshing for simulating the evolution of the water-soil interface. Mercier et al (2014aMercier et al ( , 2014b) implemented a combined Euler-Lagrange method that tracked the displacement of the soil-water interface as erosion progressed. Their findings showed that such a method can effectively model coupled changes in shear stress distribution and scour hole geometry.…”