Volume 10 Issue 4 ( December )

The piano key weir (PKW) is a spillway with inlet and outlet keys that are similar to piano keys. Depending on the water head and the width of the outlet keys, the flow into the inlet keys and through the outlet keys is directed by partition walls, resulting in a flow characteristic that differs from that of a traditional spillway. This paper presents some flow characteristics of the type A rectangular PKW and research on physical models in a laboratory flume, 22 m in length, 0.8 m in width, and 1 m in height. We found the equation that tells us how much water flows through the PKW in the full regime and the incomplete regime of the outlet key when Ho/Wo = 0.5 is the boundary value. The equation was built for flow states and convenient calculations, with an accuracy of less than 8.03% compared to experimental data. Beside, statistical indicators between measured value and predicted values are good (RMSE = 0.022; MAE = 0.017; MAPE = 2.0%), especially in correlation coefficient is strong (R² = 0.98). Using the data of other authors, the calculation efficiency of the proposed formulas is also very suitable, giving a very strong correlation coefficient (R² > 0.9) and other statistical indicators close to the ideal point (zero). This shows that the proposed equations are very suitable to evaluate the flow capacity through the PKW and effective in water management and sustainable development at river basin.

Keywords: Piano key weir; PKW; characteristic flow; physical experimental model; type A