An experimental and numerical investigation of hydraulic performance of in-channel triangular labyrinth weir for free overflow

Abstract

ABSTRACT Labyrinth weirs are well known for their superiority in providing higher flow capacity for a given hydraulic head, especially in areas where space is limited. This study presents an experimental and numerical study to determine the hydraulic efficiency of triangular labyrinth weirs. The discharge coefficient of a weir was determined in two different ways, depending on the width of the channel (C d ) and the length of the crest of the weir (C L ). Although the crest length is the most important factor in increasing the discharge coefficient per unit channel width, the discharge coefficient per unit crest length decreases with increasing the crest length for a given head. It can be said that the main reason for the reduction in weir efficiency, particularly at high headwater, is nappe interference and therefore local submergence between cycles. From the results of systematic analyses, some new highly correlated multiple regression equations calculating these two coefficients in relation to the weir geometries and the flow conditions were obtained. As a result of the literature comparison, although they were found to be generally compatible with the results of similar studies in the literature, the reasons for the differences between them were discussed.