Total Volume Conservation in Simulation of Unsteady Free-Surface~Flows

Authors: ENDER DEMİREL, İSMAİL AYDIN

Abstract: Free surface tracking methods used in the numerical simulation of unsteady free surface flows may introduce sources or sinks resulting in changes in total fluid volume in the computational domain. A computational model is developed for incompressible, 2-dimensional, unsteady free surface flows to investigate the conditions of total volume conservation. The model is based on finite volume discretization of the Navier-Stokes equations coupling momentum and mass conservation. Free surface position is tracked using a depth-integrated continuity equation. Possible free surface cell configurations and a solution procedure for continuity are described. A flux-corrected transport method is applied to the free surface solution to maintain numerical stability and eliminate unphysical surface oscillations. The discretization scheme and the computer code are validated in lid-driven cavity flow. Liquid sloshing in a partially filled rectangular tank and dam-break flows are simulated. Numerical solutions preserving total volume are presented. Computed free surface profiles are verified by experimental data.

Keywords: Free-surface flow, Unsteady flow, Dam-break, Sloshing tank, Finite volume method

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