Numerical simulation of undular hydraulic jump on smooth bed using volume of fluid method

Abstract

Undular hydraulic jumps are characterized by a smooth rise of the free surface followed by a train of stationary waves. These are sometimes experienced in natural waterways and rivers. Numerical difficulties are especially distinct when the flow condition is close to the critical value. The near-critical flow field is very sensitive to conditions of flow and channel. Furthermore, the free surface will be a wavy shape. The wavy surface may be associated with several transitions from supercritical to subcritical states and vice versa (i.e., undular hydraulic jump). In this study, a flow model is presented to predict an undular hydraulic jump in a rectangular open channel. The model is based on the general two-dimensional Reynolds-Averaged Navier–Stokes flow equations. The resulting set of partial differential equations is solved using the FLOW-3D program. To validate the model, the results are compared with experimental data. The comparison indicates that the present model can yield good results. To prove the potential application of the model, several types of undular hydraulic jumps occurring in different situations are simulated.