An experimental study with four different types of bed conditions was carried out to understand the effect of roughness in open channel flow at two different Reynolds numbers. The bed conditions include a smooth surface and three different roughness conditions, which were generated using sand grains with a median diameter of 2.46 mm. The three rough conditions include a surface with distributed...

Failures barrages or parts of them may be expected when excessive scour patterns are observed downstream of such structures. Severe and excessive scour may be largely due to unsymmetric operation of gates especially when a multi-vents barrage or regulator is being considered. Previous investigations proved that the scour patterns downstream hydraulic structures are functions of the bottom veloc...

A depth-averaged 2-D model has been developed for simulating coastal barrier breaching processes. The model solves the generalized shallow water equations and the non-equilibrium sediment transport and bed change equations in a coupled fashion using an explicit finite volume method on a rectangular grid. It considers interactions among transient flow, strong sediment transport, and rapid bed ch...

When an object is dropped into a bed of fine, loosely packed sand, a surprisingly energetic jet shoots out of the bed. In this work we study the effect that boundaries have on the granular jet formation. We did this by (i) decreasing the depth of the sand bed and (ii) reducing the container diameter to only a few ball diameters. These confinements change the behavior of the ball inside the bed,...

The average bed and sidewall shear stresses in smooth rectangular open-channel flows are determined after solving the continuity and momentum equations. The analysis shows that the shear stresses are function of three components: (1) gravitational; (2) secondary flows; and (3) interfacial shear stress. An analytical solution in terms of series expansion is obtained for the case of constant eddy...

We investigate theoretically the nonlinear evolution of sand ripples in a viscous fluid when a granular bed is submitted to a two-dimensional laminar shear flow. On the basis of the hydrodynamic equations and a semi-empirical sand transport law, we derive a non-local and nonlinear equation for the dynamics of the bed profile in the case of infinite flow depth. This equation reveals a coarsening...