Implementation of Immersed Boundary Method for Rapid and Reliable External Flow Simulations in Automotive

The conventional approach for simulating external flow field over an automobile is to use body fitted (BF) mesh. However, depending on the geometrical complexity of the boundaries, grid generation and grid quality are major issues and take significant time and cost. Moreover, preparing a proper body fitted mesh requires manual intervention which makes it too difficult to automate the process of external aerodynamics simulation. A different approach is so called Immersed Boundary (IB) method. It provides a high level of flexibility in handling highly complex geometry. It is usually employed in conjunction with body non-conforming Cartesian grid. Thus, grid generation is greatly simplified. This method can tackle flows with complex stationary or moving boundaries with relative ease. This paper demonstrates the ease of use of the IB method compared to the BF method and possible use of the IB method to automate the external aerodynamics simulations. In present work the results of front-end flow field simulations of a vehicle with complex geometry are evaluated against corresponding conventional body fitted simulations data.