Numerical simulation of A-type hydraulic jumps at positive steps

Abstract

A numerical simulation of the A-type hydraulic jump at a positive step, which is an example of mixed supercritical-subcritical flow with a discontinuity at the channel bed, is given by using an integral approach. A gradually varied subcritical flow over a rectangular, horizontal, and prismatic channel with an abrupt bottom rise is considered as the initial condition. Then, the upstream depth is decreased to a value producing a supercritical flow and remaining unchanged during computations. The resulting unsteady flow is solved by using both the MacCormack and the dissipative two-four schemes for the one-dimensional, unsteady Saint-Venant equations. In the numerical simulation, the step is treated as an internal boundary. At the downstream and the internal boundaries, the method of characteristics is employed to compute the relevant parameters. The numerical simulation is verified by comparing the results with the available data and analytical methods.Key words: hydraulic jump, positive step, numerical simulation, internal boundary.