Granular shear bed non-linear evolution: experimental determination

Abstract

The transport of granular matter as bed load by a fluid flow is frequently found in nature and in industry. Under these conditions, an initially flat granular bed may be unstable, generating ripples and dunes. This is an intricate problem because the bed undulations perturb the fluid flow, which, in its turn, generates the bed undulations. Although of importance for many scientific domains, the bed load and the instabilities of a granular bed are not well understood. This project proposes an experimental study concerning the formation of ripples and dunes (in their nonlinear phases). The bed evolution will be filmed by a high-definition camera, and the celerities and the wavelengths will be determined by post-processing the images. (AU)