A New Immersed Stress Method Based on Volume Average

Based on the volume-averaged equations for fluid-solid two-phase flow, an immersed stress method (ISM) is proposed to compute the fluid-solid interaction. As the averaging volume is explicitly defined, the reaction force on the fluid from the solid is related to the surface stress. The size of the averaging volume is comparable to the grid width to capture the flow structure in the grid scale. The reaction force based on the surface stress is computed by assuming the distributions of the velocity and the pressure. Applying the ISM to flows around a particle larger than the grid scale, the drag and lift forces are reasonably represented by computing the surface stress distribution by the ISM.