A force partitioning method to model spherical particles in liquid flows with low grid resolution

Abstract

We have extended the traditional point-force method for modeling suspended small particles to include a force partitioning approach for particles that are slightly larger than the grid size. This size range falls between the limits of applicability for both the point-force and immersed-boundary methods. In our approach, we partition the modified term of the momentum exchange between the solid and fluid phases into the grid cells based on the area and volume fraction of the solid particle contained in each cell. We demonstrate that, for particle Reynolds numbers less than 40 and using the relatively coarse grid resolution, our method yields resolution-consistent results for the flow field, which are in good agreement with those obtained using the highly resolved immersed boundary method. By incorporating our method with the immersed-boundary method to handle large-sized particles, we demonstrate the ability to efficiently model the segregation of mixed-sized particles in liquid flows.