Study of relative energy dissipation of trapezoidal and arced piano key weirs equipped with baffles

Abstract

Abstract Energy dissipation is one of the important issues in piano key weirs (PKWs). Excessive energy at the weir's toe can cause scouring. In the previous studies, energy dissipation of the arced piano key weirs (APKWs) has not been investigated. In this experimental study, the effect of weir height as well as the height and arrangement of the baffles located on the outlet key slope on the amount of dissipated energy were examined in trapezoidal piano key weirs (TPKWs) and APKWs. Experiments were performed on models with two weir height to the width of a cycle ratios equal to 0.9 and 1.2, three baffle height to the width of a cycle ratios equal to 0.06, 0.12 and 0.18 and two A and B-arrangements. The results showed that with the increase in discharge, the amount of relative energy dissipation decreases. The amount of relative energy dissipation is higher in weirs with higher height and also in weirs with larger baffles. Also, the arrangements of the baffles located on the outlet key slope has a significant effect on the amount of dissipated energy.