Author(s): Jeonghu Lee; Van Thinh Nguyen

Linked Author(s): Van Thinh Nguyen

Keywords: Ir injection; Bedload transport; LES-DEM coupling; Scour mitigation; Wall jet flow

Abstract: This study investigates the effect of air injection on scour mitigation behind an apron under a wall jet flow condition. We employed a combined large eddy simulation (LES) and discrete element method (DEM) technique within the OpenFOAM framework, further incorporating the volume of fluid (VOF) method to reproduce air flow and free surface. The dimensions of the simulated scour were in good agreement with those obtained from empirical formulas derived from a well-known laboratory experiment, indicating a reliable model. Our research focused on analyzing the flow structures and sediment behaviors when air was injected at the end of apron at various flow rates. The air injection was found to significantly decrease the bedload transport rate and the maximum scour depth by reducing the near-wall streamwise mean velocity. Moreover, as the rate of air injection increased, there was a further reduction in the maximum scour depth, accompanied by a greater increase in the near-wall streamwise turbulence intensity. The simulation results clearly demonstrate the potential of air injection in mitigating scour behind an apron, presenting it as a viable alternative approach to diminishing scouring effects.

DOI: https://doi.org/10.3850/iahr-hic2483430201-99

Year: 2024