Numerical Modelling of Hydraulic Jump Using Mesh-based CFD method and Its Comparison with Lagrangian Moving-Grid Approach

Abstract

Hydraulic jump is a phenomenon in fluid mechanics that has a high research interest due to its energy dissipating behaviour in hydraulics. This study aims to simulate a hydraulic jump using RNG k-ϵ and SST k-ω turbulence models. This study adopts the Eulerian fixed mesh approach in ANSYS FLUENT, where the free surface was modelled using Volume of Fluid (VOF) method to simulate multiphase flow of water and ambient air. Transient analysis is performed using an implicit discretization scheme. Results of open surface water levels and longitudinal velocity profiles are computed and compared with experimental result and those obtained using the Lagrangian approach. Both models show good agreement with experimental data in terms of the free surface water level, with the SST k-ω showing the most similar trend whilst RNG k-ϵ providing a better roller length. The SST k-ω model showed the poorest performance in predicting the mean longitudinal velocity profile as compared to the RNG k − ϵ model.