Clear-water local scour around pile groups in shallow-water flow

Abstract

The results of an experimental study on clear-water scour at pile groups under steady flows at threshold velocity are presented. A wide range of pile group arrangements, spacing, and submergence ratios are studied. Uniform bed material in a 46-m long, 1.52-m wide, and 1.9-m deep flume was used to obtain comprehensive data. Empirical relations to demonstrate the effects of the studied variables are presented. On the basis of the findings of this study, a new method to predict the effect of pile group arrangements, pile spacing, and submergence ratio on local scour depth is proposed. The experimental data obtained in this study and data available from the literature are used to evaluate predictions of existing methods and the accuracy of the proposed method. The proposed method gives reasonable scour depth predictions.