Numerical Simulation of Free Surface Flow Using a Multiphase Model with Higher Order Scheme.

The flow of water can be modeled by either single phase flow or multiphase flow approach. Despite having the advantage of avoiding discontinuity at the free surface normally faced in single phase model, the multiphase model is still facing the difficulty to advect the sharp interface between two fluids. This study attempts to validate a multiphase model with a third-order accurate scheme for two-dimensional flows with free surface based on the Volume/Surface Integrated Average Multi-Moment Method (VSIAM3). For a sharp and smearless free surface, the Tangent of Hyperbola for Interface Capturing (THINC) scheme is applied in the numerical model to advect the volume of fluid (VOF) function. The advection term in the Navier-Stokes equation is solved using the third-order constrained interpolation profile-conservative semi- Lagrangian (CIP-CSL3) scheme. The performance of the numerical model is checked by simulating the classical dam-break problem with and without an obstacle. Results show that the conservation of fluid volume for both cases are within 0.6% during 1 s of simulation. Satisfactory agreements are observed between the numerical and the previous experimental results in term of the development of free surface profile. For the case of dam-break flow without an obstacle, the variation of the propagation of front wave and the attenuation of depth at the origin between the experimental and numerical results are less than 10% and 1%, respectively. [ABSTRACT FROM AUTHOR]