A Study of pressure fluctuation caused by hydraulic jump in stilling basin

A stilling basin is one of the energy dissipaters downstream of a spillway. The place of maximum pressure caused by jet impact and the effect of various factors on the amount and location of pressure are important factors in designing of stilling basin. Extensive experimentally and few numerically researches have been carried out in this regard. In this research, dynamic pressure fluctuations on the basin floor are studied using two phase flow finite volume numerical method considering different geometries of ogee spillway and sharp crested weir, height of spillways, different flow velocity, Froude number and type of stilling basin. Firstly, numerical results were compared with the experimental ones and relative errors of 8% to 12% have been achieved in this comparison. The results of numerical analysis of spillways with height of 5,7,9,11 and 15 meters and Froude numbers between 3.7 to 6.2 for ogee spillways and between 4 to 6.8 for sharp crested weirs showed that, hydraulic jump happens in 1/3 of the beginning of the stilling basin in all spillways. Maximum pressure fluctuations increase from 62000 to 144000 Pa for ogee spillways and 54000 to 156000 for sharp crested weirs with the height of spillways. The influence of types of stilling basin on maximum pressure fluctuations is also evaluated.