430 / 2024-03-15 22:53:28

Radial distribution of hydrodynamic pressure fluctuations at plunge pool bottom

Plunge Pool,Dynamic Pressure,Radial Distribution,Plunging jets,Froude Number

Subtheme 3: Eco-hydraulics and Environment > Topic 3: Eco-environmental Effect of Water Engineering

Hydrodynamic pressures at the bottom of plunge pools are crucial in estimating the depth of rock scour in unlined plunge pools. By determining the radial distribution of dynamic pressures, designers can calculate the extended geometry of the scour hole to ensure the stability of the dam structure. This study presents experimental results of pressure measurements at the bottom of the plunge pool subject to circular plunging jets. The mean and fluctuation characteristics of dynamic pressures are assessed using the C_P and C'_P coefficients, respectively, as a function of the plunge pool Froude number, Fr_P (=V_j/(g.Y)^0.5, where V_j is jet velocity at plunge pool surface and Y is pool water depth). The Fr_P considers the effects of both jet velocity and pool water depth. The results show that the pressure intensity within the footprint of the plunging jet at the pool bottom remains high, approximately equal to the pressure order at the stagnation point. Dynamic pressure fluctuations decrease as the radial distance of jet impact increases. When the radial distance is four times the initial jet diameter, dynamic pressures tend to zero. Empirical models of the radial distribution of pressure fluctuations are presented, which are more efficient for practical purposes.