Performance Analysis of Immersed Boundary Method for Predicting External Car Aerodynamics
2022-01-1087
03/29/2022
- Event
- Content
- Computational Fluid Dynamics (CFD) is a well-established method for the evaluation of the aerodynamics properties of a car. Lattice Boltzmann (LB) and finite volume (FV) are the most frequently used methods for such simulations. Many users are more confident with the FV method due to various advances in the Reynolds-Averaged Navier-Stokes (RANS) near-wall turbulence modelling. FV method primarily employs RANS models, whereas so-called scale-resolving models are increasingly used for high-fidelity analyses. The accuracy of RANS near-wall models relies on the mesh quality near the wall so by the rule, larger number of body-fitted cell-layers are employed at the wall. An immersed boundary (IB) method could be attractive alternative to the ‘standard’ approaches mention above, especially when applied to low quality CAD data. In general, this approach is less investigated and validated for car aerodynamics, particularly in conjunction with advanced near-wall turbulence models. In this ‘meshing-less’ approach there is a background volume mesh and a surface mesh intersecting with the background mesh. Adaptive mesh refinement must be applied on the cells cut with the surface to properly capture geometry details and improve accuracy of the predicted flow features. RANS turbulence model adopted in this work is k-z-f model which is less sensitive to the wall-normal distance than most of RANS models. Scale-resolving simulations are performed employing Partially Averaged Navier-Stokes approach, which relies on the same RANS model, hence both strategies are well suited for the IB approach. The results obtained by the IB method will be compared to the experimental data of Hupertz et al. (SAE 2021-01-0958) obtained for the well-known DrivAer notchback model but also to the reference calculations on the body-fitted mesh. The paper aims at demonstrating predictive capability of the IB method, particularly suitable when large number of different exterior design configurations are to be investigated.
- Citation
- Basara, B., Zunic PhD, Z., Pavlovic, Z., Sampl, P. et al., "Performance Analysis of Immersed Boundary Method for Predicting External Car Aerodynamics," SAE Technical Paper 2022-01-1087, 2022, .