Multiscale Modeling of Flood-Induced Surface Erosion in a Particle Bed Yasser Abdelhamid Advisor: Dr. Usama El Shamy Department of Civil and Environmental Engineering Southern Methodist University, Dallas, TX 75275

Introduction Experimental observations show that if the fluid flow velocity exceeds a certain value, the particles in the upper layers of the bed would start moving (sheetflow). Surface erosion is a particle level phenomenon and therefore, a numerical model that is capable of tracking the behavior of the particle bed at microscale is needed. Sheetflow Layer Stationary Bed 1) Sheetflow mechanism. 2) The microscale effect.

Coupled Fluid-Particle Model Using a microscale model that can model both phases at microscale level Fluid velocity inside the soil pores

Coupled Fluid-Particle Model Discrete solid phase: Newton’s second law of motion: Fluid phase: The equation that describes the collision and streaming in a timestep: Linear momentum Angular momentum Using a microscale model that can model both phases at microscale level Fluid velocity inside the soil pores D2Q9 model

Particle Bed Simulations Highlight that the initial bed surface @ y=0

Particle Bed Erosion U=2.0 m/s 1) Sheetflow then lift and leave the particle particle bed +erosion takes place (layer by layer)