Numerical study of a symmetric submerged spatial hydraulic jump

Hydraulic jumps are often employed as energy dissipators below hydraulic structures. If a high-velocity conduit drains into an expanding open channel a spatial hydraulic jump can be formed. Even though this type of hydraulic jump is common in civil engineering practice, it has not received sufficient consideration by researchers. Three-dimensional, unsteady detached eddy simulation of a symmetric submerged spatial hydraulic jump was carried out to evaluate the turbulent flow features. The volume of fluid multiphase model was used to capture the free surface. The complete three-dimensional flow features of symmetric submerged hydraulic jump are reported herein for the first time. The three-dimensional jump roller was found to be stronger near the side walls than at the centre. The instantaneous vortex shedding from the conduit outlet was also captured by the simulations. To describe the internal structure of turbulence within a symmetric submerged spatial hydraulic jump, the coherent flow structures are qualitatively and quantitatively examined using a vortex identification technique and proper orthogonal decomposition.