Technical Paper
Automatic Mesh Motion with Topological Changes for Engine Simulation
2007-04-16
2007-01-0170
Computational fluid dynamics (CFD) codes today represent consolidated tools that cover most physical and chemical processes which occur during operation of internal combustion engines under steady and unsteady conditions. Despite the availability of advanced physical models, the most demanding prerequisite for a CFD engine code is its flexibility in mesh structure and geometry handling capacity to accommodate moving boundaries. In fact, while the motion is solely defined on boundary points, most CFD approaches a-priori specify the position of every mesh vertex in the mesh for every time-step. Alternatives exist, most commonly using mesh generation techniques, like smoothing. In practice this is quite limiting, as it becomes difficult to prescribe solution-dependent motion or perform mesh motion on dynamically adapting meshes. To preserve the mesh quality during extreme boundary deformation due to piston and valve motion, the number of the cells in the mesh needs to be changed.