Hydraulic Design of Circular Sectioned Labyrinth Weirs and Comparison With Triangular Formed Labyrinth Weirs

Abstract

Spillways are the hydraulic structures, transfer excessive water from reservoir to downstream side safely and controlled manner. A labyrinth weir is flat spillway that folded in plain view. Labyrinth weirs provide many advantages compared with the linear weirs. Labyrinth weirs increases crest length for a given channel width and increase the discharge capacity for a particular total head. As a result of increased flow capacity, labyrinth weirs require less space on the dam body compared to linear weirs. In this study, a new hydraulic design and analysis method is carried out to increase efficiency of the labyrinth weirs. Triangular and trapezoidal labyrinth weirs have been redesigned in circular form in order to make the regions at the intersection corners that reduce the flow capacity more efficient and allow the flow move perpendicular to weir walls. Another advantage of circular sectioned labyrinth weirs is that it provides longer crest length than triangular form. In circular sectioned labyrinths, the flow is exposed to less number of intersection points and discharge capacity is increased. Experiments are conducted on 3 setups for triangular weirs (containing 2, 3 and 4 triangles) and 3 setups for circular sectioned weirs (containing 2, 3 and 4 circles). Experiments were carried out on 6 different setups at total and all setups have P=20 cm weir height (P). A total of 180 data were collected, 30 data from each setup. The results obtained from circular and triangular formed labyrinth were compared and it was seen that the circular formed labyrinth weirs have a higher discharge capacity.