Evaluation of the Level-Set and Anti-diffusion Functions Influence in the Simulation of Non-Newtonian Dam Break Problems

Dam break flows are characterized by the rapid release of some reserved liquid. In addition to the obvious interest in this type of study to prevent problems related to civil infrastructure, it is also a type of flow widely used as a numerical test for immiscible multiphase problems. Many fluids existing in nature and in industry behave as non-Newtonian ones, which makes their study very important in several areas of engineering. In this work, the effects of interpolation functions for interface capture in dam break problems involving viscoplastic fluids are investigated. The multiphase problem is solved using the volume of fluid method (VOF) in isolated form, and together with both level-set and anti-diffusion. Ansys-Fluent can use four interpolation functions: PLIC (Geo-Reconstruct), CICSAM, Modified HRIC and COMPRESSIVE. The influence of the both level-set and anti-diffusion is investigated for all four interpolation functions. The analysis of the qualitative interfacial resolution of the four interpolation functions showed that PLIC is superior to the other functions in standard configurations. The influence of complimentary algorithms, such as level-Set and anti-diffusion, indicated that their use can improve interfacial quality and sharpness of the CICSAM, Modified HRIC and COMPRESSIVE interpolation functions to a comparable level of quality and sharpness. The analysis of the quantitative parameters reveals however, that the increase in the computational time is still a drawback of the methodology. No significance in gain or loss of mass were found in any simulation.