ANALYSIS OF FLOW OVER TRIANGULAR (PLANFORM) LABYRINTH WEIR MODELS

Abstract

In this project, analysis of flow over different models of triangular labyrinth weir is done with the help of ANSYS (Fluent) software. Different weir geometries are designed and analysed under similar condition to determine the optimum geometry among the tested ones. The need for labyrinth weir arises at the places where the width of channel is less and discharge increases. In the case of limited width, a straight weir causes the increase in the reservoir’s water level which consequently leads to a greater area of submergence. To avoid this head upstream, which can cause much damage, the labyrinth weir was developed. The objective here is to reduce the upstream head of triangular labyrinth weir and obtain a relationship between increasing or reducing head with respect to side angle α, effective length L and cycle of weir N. The numerical modelling of a Triangular labyrinth weir is done with the help of ANSYS and the pressure distribution, velocity contour, and depths of flow is studied using contour maps which shows the variable distributions at upstream and downstream of the weir. Total 9 models are designed in ANSYS fluent and all models are simulated under same conditions i.e. same discharge and same channel width and length. Due to different crest lengths, weirs behaved slightly different and H is obtained for each case. The coefficient of discharge is calculated to differentiate in efficiency of different weirs. Also, some non-dimensional parameters are calculated to compare with previous trends.