Flow resistance due to a single spur dike in an open channel

Abstract

A method for quantifying the flow resistance exerted due to a single spur dike located in an open channel is presented. The work was carried out in a rigid bed flume, with the model spur dike being simulated using various sizes of a rectangular plate. The drag force exerted by the spur dike plate for both submerged and un-submerged flow conditions was directly measured using a specially-designed apparatus and also by applying the momentum equation to a control volume that included the plate. The results indicate that an increase in the blockage due to the spur dike plate is the main parameter responsible for an increase in the spur dike drag coefficient, hence the associated flow resistance. Based on the present experimental results, relationships are given to estimate the backwater effect due to a single spur dike.