A common difficulty in simulations of complex fluid flow problems is that not every geometry especially for the case of relative motion between components can be well represented using a single, contiguous grid. Overset grids can be used to track relative motion with computational efficiency. Recent advances in high performance Computational Fluid Dynamics (CFD) software have enabled the coupled simulation of multiphase fluid flow and rigid body motion in overlapping overset grids.
A CFD method is developed and applied for the simulation of oil flow in multiple rotating spur-gear systems with emphasis on pressure torques and flow fields between adjacent gear teeth. The concept of multiphase flow is based on the volume of fluid method. The results show that the applied CFD method is convenient to study different oil filling depths in a gearbox with respect to their influence of flow and pressure distribution. Interpolation criteria between overlapping grids and proper values of mesh size showed to be important for prediction of oil volume distribution.