# Wolf Dynamics - Multiphysics simulations, optimization, and data analytics

## OPENFOAM VALIDATION CASES

DrivAer validation case - Automotive simulation

Hereafter, we compute the flow about the DrivAer model [1]. This is an automotive validation case that has extensive experimental data [1, 2, 3]. The simulations presented in this validation case, were conducted for the fastback and smooth underbody model.  The inlet velocity corresponds to 30 m/s, the ground is moving with a translational wall boundary condition, and the wheels are rotating with a rotational wall boundary condition.

The simulations were conducted using simpleFoam and the k-Omega SST turbulence model with wall functions. The boundary and initial conditions for the turbulence quantities were computed using the guidelines described in reference [4]. At the outlet of the domain, we used backflow treatment.

 Drivaer model. The geometry corresponds to the fastback and smooth underbody model [1]

 Boundary  conditions

 Moving wall boundary  conditions

 Visualization of vortical structures using Q-criterion

 Visualization of velocity magnitude contours in the symmetry plane. Visualization of pressure contours and streamlines of the model surface.

 Drag coefficient iterative converge. Setup 1: no rotating wheels, moving ground. Setup 2: rotating wheels, moving ground. Setup 3: rotating wheels, no moving ground. Setup 4: no rotating wheels, no moving ground.

ReferenceMean $$c_d$$
Current validation study (Setup 2) - OpenFOAM0.2426
Ref. [2] - EXP PVT UC0.243
Ref. [2] - EXP PVT0.228
Ref. [2] - EXP TUM ASME0.247
Ref. [2] - EXP TUM SA0.243
Ref. [2] - NUM US:200M0.235
Ref. [2] - NUM SS-EWT:200M0.214
Ref. [3]0.258

Table 1: comparison of experimental and numerical results. Setup 2 corresponds to the simulation with moving ground and rotating wheels.

 Residuals iterative evolution. Only the first 1000 iterations are shown.  All the simulations were run up to 5000 iterations.

warning The experimental values were extracted from plots illustrated in references [1, 2, 3].
We can not guarantee the accuracy or precision of this information.

References:

[1] http://www.aer.mw.tum.de/en/research-groups/automotive/drivaer/

[2] Steady and Unsteady Numerical Analysis of the DrivAer Model. R. Yazdani. Chalmers University of Technology, Master Thesis, 2015.

[3] Experimental Comparison of the Aerodynamic Behavior of Fastback and Notchback DrivAer Models. SAE Technical Paper 2014-01-0613, 2014.

[4] https://turbmodels.larc.nasa.gov/