Volume of fluid model for an open channel flow problem

Abstract

In the past, the solutions to open flow problems were generally found on the basis of experimental data or through the development of theoretical expressions using simplified assumptions. The volume of fluid (VOF) turbulence model can be applied to obtain the flow parameters such as pressure head distributions, velocity distributions, and water surface profiles for flow in open channels. The free overfall in a rectangular open channel that serves as a discharge measuring structure is selected to apply to the VOF model. The predictions of the proposed VOF model are validated using existing experimental data for both subcritical and supercritical flow approach conditions. Based on the path followed by a fluid particle leaving the brink section, the equations for the nappe profiles in supercritical flows are obtained in terms of the end depth. The VOF turbulence model developed is used to predict the characteristics of a free overfall in a rectangular open channel.Key words: turbulence model, VOF model, numerical simulation, overfall characteristics, open channel flow.