Scale effect in pier-scour experiments

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, how, and loose-bed particles-a condition that is rare. Geometric similitude is an important prerequisite to dynamic similitude in replicating local energy gradients for flow around piers. The implications for laboratory experiments on local scour and for design estimation of scour depth are discussed.