Pier Width and Local-Scour Depth

Presented here are the results of an enquiry into the effects of pier width on local scour depth. The results show that scour depth does not scale linearly with pier width unless there is more-or-less complete geometric similitude of pier, flow, and loose-bed particle; a condition that is rare. Geometric similitude is an important prerequisite for dynamic similitude, in replicating local energy gradients for flow around piers. The implications for laboratory experiments on local scour, and on design estimation of scour depth, are discussed.