Wall shear stress in open channel flow using different configurations of groynes

The effects of groyne geometry and arrangement on wall shear stress in a straight channel are studied by means of Computational Fluid Dynamics (CFD) software. Two- and three-dimensional models including pressure-velocity coupling scheme SIMPLE and the (Formula presented.) equations are used to show that the 2D model can adequately predict flow in comparison to 3D cases, reducing computing time considerably. The numerical procedure is validated by comparing numerical results with experimental measurements obtained from a laboratory-scale glass open channel with no bed sediments. Operating parameters are calculated by the Froude similarity study of a real-scale channel situation. The validated scheme is used to analyze the wall shear stress behavior in terms of groyne geometry and, in the case of multiple configurations, of the optimal distance between them. In all the considered settings, the presence of groynes causes an increase in the wall stress on the opposite margin and a decrease in the margin of groyne location. The shorter the groyne length, the smaller the rise on the shear stress on the other margin. The most significant reduction of the wall shear stress on the groyne margin is obtained with three groyne configurations.