EFFECTS OF PLUNGE POOL DIMENSIONS ON DYNAMIC PRESSURES ON SIDEWALLS DUE TO JET IMPACTS

Plunge pool is one energy dissipation structures for high head which ensures stability of the dam under extreme hydrodynamic pressures due to the falling jet impacts. The excess energy of the jet is dissipated together with significant dynamic pressure exerted on the floor and pool walls. Hydrodynamic pressure fluctuation is on important parameter for design of plunge pool floor and sidewalls. Thus, appropriate assessment of jet dynamic characteristic in the plunge pool is essential . this research present the experimental results, focusing on distribution of mean and extreme pressure fluctuations on the sidewalls due to circular and rectangular plunging jets and effect of pool, dimensions especially in narrow valleys. The investigated variable are; discharge geometry of jet, pool depth ,pool width and side walls slope. Results show that decreasing bottom wisth from 6 to 3 times the jet impact width or increasing the sidewall slope increases the maximum pressure and decreases the minimum and mean dynamic pressures on the sidewalls for core jet impact condition, while in case of developed jet impact a reverse effect is deduced for mean dynamic pressure.

Keywords:

Plunge pool , Circular and rectangular jets , Hydrodynamic presseure , Experimental model