Institute of Fluid Machinery

CFD-Code - Research - Immersed Boundary Method

Development of CFD-Code: PACER

The simulation of complex three-dimensional flows requires an enormous effort in generating the mesh. This leads to the development of the CFD-Code PACER (PArallel Code for Education and Research). Starting with a surfacetriangulated geometry an unstructured cartesian volumetric mesh is obtained by means of a raytracing algorithm. This is especially advantageous for geometries with moving boundaries where a new mesh is needed at every timestep.






The geometry cuts through the cells of the mesh which is therefore non-body fitted. The boundary conditions need a special treatment according to the Immersed Boundary Method (IBM). The values of an additional external cell are hereby extrapolated from neighbouring internal cells in such a way that the boundary condition is exactly fulfilled.





In complex geometries there are plenty of special cases to consider in order to ensure generality. The algorithm is verified and optimized by simulating laminar flows combined with simple geometries. Future development involves mesh refinement, turbulence modelling and convergence acceleration methods.