Effect of inlet flow condition on hydrodynamic parameters of stilling basins

In the present study, the effect of inlet flow condition of a stilling basin on the hydrodynamic parameters of flow as well as velocity and pressure distributions, vorticities, pressure fluctuations, turbulence intensities, and hydrodynamic loads were investigated. To do so, two practical and usual cases of flow at the downstream of a bottom outlet and downstream of a chute spillway were simulated and analyzed. To verify the numerical simulations, a scaled physical model was employed. Large eddy simulation and volume of fluid models were used to simulate the turbulence and free surface, respectively. Results showed that when moving the place of the formed hydraulic jump at the first 25% length of the stilling basin, pressure fluctuations were on average 42.6% more at downstream of the chute spillway in comparison with bottom outlet. However, in the middle of the stilling basin length due to the impact of the jet at the downstream of the bottom outlet model, the pressure fluctuations were on average 47.3% more than the pressure fluctuations at the downstream of the spillway model. The maximum values of vorticity and turbulence intensity occurred in the section of hydraulic jump formation in the stilling basin.