مهندسی منابع آب (Jan 2017)
Finding Potential of Increase in Water Level at Piano Key Weirs using Physical models
Abstract
The Parapet Walls were installed on the top of PKW crest. There slopes were investigated with the 3.0 co-flow angles 3. 5.5 and 8 Degrees (positive slops) and counter-flow slopes (negative slopes). The Parapet Wall heights were 2.5, 4.5 and 6.5 cm on the two models. The experiments were conducted on a PKW with the P/WU=1.33 and P/W=0.5(P=Spill way height; Wu=width of one cycle. W=ouHetkey with). The test were performed on on experimental model with the length, width and height of 10.00, 0.80, and 0.60 meters, respectively. The results indicated that the model with the P/WU=0.5 was more effective in raising the water level that of P/WU=1.33 . The Results However the influence of positive or negative slopes was ineffective in increasing the angle of parapet wall. Furthermore, it was found that the discharge coefficient and Ht/P were increasing up to the peak discharge and reversed afterwards. Generally, a horizontal parapet wall increases the discharge coefficient up to 15 percent. The coefficient of determination (R2) between that discharge coefficient and the slope of parapet walls was 0.977 and statistical parameters NRMSE and WQD, 0.147 and 0.004, respectively.
