Groyne spacing role on the effective control of wall shear stress in open-channel flow

摘要

The objective of an effective configuration for a series of groynes in an open channel is the attainment of large bed shear stress in the main channel for channel deepening and small sidewall shear stress in the groyne fields for bank protection with the lowest cost, i.e. with the largest spacing between groynes. A Reynolds-averaged Navier-Strokes, finite-volume, numerical model was used and it was validated against experimental data for the case of a single groyne. For series of groynes with uniform spacing between them, the most effective configuration was the one with spacing equal to six groyne lengths. For the range of parameters considered, a substantial improvement of the effectiveness was achieved by implementing a novel non-uniform configuration where the spacing between groynes was reduced to one and a half groyne lengths in the first four groyne fields, and remained equal to six groyne lengths in the subsequent ones.