A numerical flume with enhanced momentum conservation for the two-phase flow simulation

The numerical simulation of two-phase flow with Navier-Stokes equations is often hampered by the instabilities rises across the interface of the different fluids. The interfacial gradient of velocity and density leads to the unphysical momentum change, resulting in an ill-defined velocity field and twisted interface. To deal with this problem, we developed an interfacial treatment which enhances the interfacial continuity of momentum (EMC treatment) [1]. Charactered by a momentum-based velocity reconstruction process and a strong coupling scheme between the N-S equation solving and interface capturing, the proposed EMC treatment can mitigate the interfacial instability and improve the accuracy and smoothness of the interface. An FDM-based flume with the EMC treatment is established based on the open-source REEF3D code [2]. Cases have been simulated for validation of EMC treatment, including pure numerical cases with idealised settings, as well as the experiments with highly deformed breaking wave [3], to demonstrate its effectiveness.