Effect of Lee‐Wake on Scour Below Pipelines in Current

Abstract

The results of an investigation of the effect of lee‐wake on scour below pipelines in currents are reviewed. The subject is investigated both experimentally and numerically. The experiments show that the scour downstream of the pipe is apparently governed by the action of an organized wake flow, which is an agglomeration of large‐scale vortices which are shed from the pipe and steadily convected downstream. The experimental results lead to a clear understanding of the effect of lee‐wake on the scour phenomenon. In the numerical part of the study the so‐called cloud‐in‐cell method is employed to predict the flow. The results appear to reveal almost all the features of the organized wake flow shown by the experiments. The theoretical calculations demonstrate that the time average bed shear stress is not a suitable parameter to work with in mathematical‐model studies of lee‐wake scour.