Prediction of Discharge Coefficients for Trapezoidal Labyrinth Weir with Half-Round (HR) and Quarter-Round (QR) Crest

A labyrinth weir allows more flow for a given head and channel width relative to other linear weirs due to the additional crest length. Earlier research explored the correlation between discharge magnification ratio to head to weir height ratio for a different configuration. Discharge coefficient depends on head to weir height ratio, crest shape, crest thickness, apex configuration, and sidewall angle. Continued efforts have been made to develop an equation for discharge coefficient in terms of these parameters. Several equations relating discharge coefficient with head to weir height ratio using polynomial fit up to sixth order for each side wall angle are available in literature. Some investigators related the coefficients of polynomial with side wall angle resulting in a complex form of equation for the discharge coefficient. An attempt has been made to develop a relatively simple discharge coefficient equation involving lesser number of coefficients in terms of head to weir height ratio and sidewall angle. Some of the salient features of the study are described in the present paper.