March 6 - 8, 2017 | Berlin
LEADING ENGINEERING SIMULATION CONFERENCE
All major automotive OEMs require fast and reliable processes for virtual simulation in order to steer a design process that proceeds at an increasingly tight pace.
Meshing process is still one of the crucial aspects that impacts on accuracy and repeatability of the CFD analyses. Repeatability and uniformity among users can be addressed via standardization and scripting, but adherence to standards is not a guarantee of accuracy in itself. Even in presence of well-established standards, the adequacy of the mesh to resolve any flow features around a specific vehicle still needs to be checked manually.
Traditional practices for automotive CFD make use of local mesh refinements around vehicles, based on previous experience and ad-hoc validations. This method makes mesh convergence analyses impractical in production environments, as the number of volume cells rapidly increases with successive refinements.
An alternative approach is the application of mesh adaption techniques, in which mesh spacings are prescribed based on local flow quantities. In this paper an application of mesh adaption capabilities of STAR-CCM+® to external aerodynamics of fully detailed vehicles will be described. The main advantage of this method is the efficient utilization of cells in capturing flow features, making it possible to achieve mesh independency at a fraction of the computational cost needed with traditional techniques. The results from traditional and adapted meshes will be compared, and the differences in the flow field around specific regions of the vehicle will be highlighted. Finally, the steps still needed to implement this technique in a product development process will be commented.