Turbulent Flow Simulation Around DrivAer Vehicle Solved By Using CF-MESH+ And OpenFOAM

London, UK, March 2019 – Creative Fields, a provider of state-of-the-art CFD meshing software, is proud to announce that the turbulent flow simulation around the DrivAer vehicle was solved successfully using CF-MESH+ in combination with OpenFOAM. CF-MESH+ is a fully automated and easy-to-use CFD meshing software solution, that features superior capabilities for mesh generation in arbitrary complex geometries.

The process

The generic DrivAer model for external flow was introduced in 2011, to narrow the gap between the overly-simplified models commonly used in automotive aerodynamics investigations (e.g. Ahmed body) and the highly complex production cars. CF-MESH+ was used to automatically generate a volume mesh around the DrivAer vehicle from a few simple specifications. The volume mesh was then successfully used in turbulent flow simulation around the vehicle by using OpenFOAM.

“We are proud of yet another successful case where CF-MESH+ has proven an excellent companion to OpenFOAM when it comes to automotive aerodynamics. Advanced boundary layer generation capabilities and the ability to control the layer thickness in the first cell near the wall make CF-MESH+ an ideal candidate for mesh generation in external aerodynamics simulations.”

Mario Baburic, Managing Director at Creative Fields.

The process of automatically generating a suitable mesh for automotive turbulent flow simulation was straightforward.

1. DrivAer geometry was obtained from TU Münich and imported into CF-MESH+, where a bounding box around the vehicle was added.
2. Each side of the bounding box was then named differently in order to define the boundary conditions required by the simulation setup.
3. The geometry of the DrivAer car was separated into multiple patches and set with different mesh refinement levels to enable feature edges to be automatically generated between patches in CF-MESH+ and allow for geometry details that require finer mesh resolution.
4. 10 boundary layers were specified on the bottom surface of the bounding box and around the car geometry.
5. A Cartesian volume mesh with 25 million cells (96% of which are hexahedral) was obtained automatically by using CF-MESH+ (v2.2.1).

The automatically generated mesh has no sudden cell size change, instead every cell size change is resolved gradually, regardless of its position (further from the car geometry or in the boundary layer), which has a positive impact on the stability of the calculation and its convergence.

The generated mesh was then used for simulation of the incompressible turbulent airflow around the vehicle using OpenFOAM solver simpleFoam and k-ω SST turbulent model which achieved convergence after 400 iterations after which a quasi-steady solution was obtained.

The entire case is now available for download, as well as in our meshing gallery.

If this post has made you curious, feel free to try out our latest CF-MESH+, designed to alleviate the pain of meshing. You can also subscribe to our newsletter to stay informed on our newest developments.

About Creative Fields

Creative Fields was founded in 2014 with a vision to become a CFD meshing champion by providing competitive and creative solutions to meet CFD meshing needs. Our focus is being at the frontiers of the latest developments in CFD meshing enabling the best value-for-money proposition on the market for CFD meshing. Creative Fields operates from offices in London (UK) and Zagreb (Croatia).

• Our Common Meshing Terminology
• Low-RE turbulence modelling of boundary layers with CF-MESH+
• Is it always the mesh? Part 6: Feature edges and corners
• Optimized CAD-to-Mesh: A Comprehensive Guide to Enhanced Workflow
• Is it Always the Mesh? Part 5: Boundary Layer Meshing