Author(s): Shanshan Li; Guodong Li; Yuan Hu
Keywords: Discharge efficiency; Hydraulic characteristics; Numerical simulation; Parameter optimization; Piano key weirs
Abstract: A piano key weir (PKW) is a solution for improving the efficiency and safety of reservoirs and simplifying their management. To investigate the influence of the inlet/outlet width ratio W i / W o on the discharge efficiency of PKWs, a three-dimensional numerical model based on a standard k − ε turbulence model and volume-of-fluid (VOF) method is employed, and the flow characteristics of nine laboratory-scale PKWs with different W i / W o ratios are studied numerically. The results confirm that PKW configurations with W i / W o > 1 are generally superior to those with W i / W o 1 in terms of discharge capacity. However, as the water head rises, the discharge efficiency of the PKW with a greater W i / W o decreases more rapidly. By decomposing the total discharge into inlet, lateral and outlet components, according to the flow features of each overflow crest and their contributions to the total discharge, the intrinsic influencing mechanism of W i / W o on the discharge performance of PKWs is revealed.