Abstract
It is important for designing river structures and those maintenances to clarify flows downstream from a negative step with hydraulic jump of which patterns depend on downstream water depth. In this study, assuming the case in which the bed is covered with relatively large roughness, an enhanced depth integrated model is developed to calculate various hydraulic jump patterns generated downstream from the negative step. The present method is based on GBVC4-DWL, which is a non-hydrostatic depth integrated model with employing a dynamic rough wall law for bed. The model with the virtual bed slope behind the negative step and the critical slope of wave breaking is validated through the comparisons with the experimental results. Then the effects of equations and terms which compose the present method on the flow downstream of the negative step are investigated with several calculation models including GBVC4-DWL, GBVC3, SBVC3 and 1DC. The comparison shows the role of velocity distribution varied with vorticity production and non-hydrostatic pressure distribution.
