Rapid granular free-surface flow past a cylindrical obstacle
Abstract: We report experimental and numerical results for the granular free-surface flow past a cylinder. A detached shock, at which the velocity and thicness are discontinuous, is generated at the front of the cylinder. On the lee-side, the granular material separates from the obstacle and a particle free region develops. This "vacuum" region closes-up rapidly in low Froude number flows and much more slowly at high Froude numbers. Experimental PIV measurements are compared to the results of simulations using a a hydraulic-type model that is solved using a non-oscillatory central finite-difference scheme.