사각형 광정위어를 통과하는 자유수면 흐름 수치모의

Abstract

Numerical simulations of free surface flow over a broad-crested rectangular weir are conducted by using the volume of fraction (VOF) method and three different turbulence models, the k-e, RNG k-ω and k-ω SST models. The governing equations are solved by a second-order accurate finite volume method and the grid sensitivity study of solutions is carried out. The numerical results are evaluated by comparing the solutions with experimental and numerical results of Kirkgoz et al. (2008) and some non-dimensionalized experimental results obtained by Moss (1972) and Zachoval et al. (2012). The results show that the present numerical model can reasonably reproduce the experimental results, while three turbulent models yield different numerical predictions of two distinct zones of flow separation, the first zone is in front of the upstream edge of the weir and the second is created immediately behind the upstream edge of the weir where the flow is separated to form the separation bubble. The standard k-e model appears to significantly underestimate the size of both separation zones and the k-ω SST model slightly over-estimates the first separation zone in front of the weir. The RNG k-e model predicts both separation zones in overall good agreement with the experimental measurement, while the k-ω SST model yields the best numerical prediction of separation bubble at the upstream edge of the weir.