Generation of incident wave in two-phase flow simulation based on field decomposition

Abstract

Field decomposition is an effective strategy for reducing numerical dissipation and dispersion. This strategy was employed by Li et al. (2021) to generate incident waves in two-phase flow simulations. This study attempts to improve previous methods in two ways. First, the density gradient in the additional source term, i.e. a delta function at the interface, is explicitly discretised. Although the explicit calculation simplifies the implementation, an additional pressure translation correction method is proposed to ensure numerical stability and accuracy. Second, the coupled level-set and volume-of-fluid method is used for interface capture. The calculation of the additional source term is more precise using the level-set function. The two proposed improvements result in a second-order spatial accuracy for the wave amplitude. A test on wave propagation over a flat bottom shows that the proposed method provides more accurate predictions of the wave amplitude compared with the previous method. In other test cases, including wave propagation over two-dimensional breakwater and three-dimensional shoal, the simulation results show good agreement with the experimental data.