Ever-evolving automotive technology entails an increasing complexity associated with its functionalities as well as safety. Faster speeds lead to more vibrations and a greater risk of lift-off. To safeguard the ‘car+driver’ system in addition to enhancing the performance of a car, it is imperative for automotive engineers and manufacturers to consider the aerodynamics involved.
Simulation acts as an apposite tool to help determine the behaviour of the system in response to the airflow around/through it. Using this information, several refinements to the car design can be made in an iterative process. With the end goal of optimizing the final design, each component of the car can be analyzed with great ease and effectiveness.
The current project aims at carrying out an aerodynamic analysis around a Formula-1 race car travelling at 215 km/h. With the help of the SimScale platform, we intend to simulate this system, taking into account the realistic constraints. Our project utilizes a pre-existing CAD model for the simulation and interprets the results to suggest meaningful design modifications.
The initial geometry for the CAD model has been imported from GrabCAD, provided by GrabCAD member ̶ Orion. For the analysis, the CAD model has been simplified, cleaned and significantly reconstructed. The cleaned geometry can be seen in the figure below:
F-1 Car: Isometric View
F-1 Car: Front View
A manual hex-dominant mesh was created in SimScale. The fluid region around the car (air) is meshed to model a Virtual Wind Tunnel. This operation gives the user more control and enables the complex geometry to be meshed accurately while keeping the overall mesh size to a suitable value. Prior to meshing, the surfaces are clubbed into topological entity sets. This facilitates the assignment of refinement levels for small and large surfaces as required.
Virtual Wind Tunnel in SimScale
Resultant Mesh on Car and Immediate Surroundings
A fine quality mesh with individually adjustable parameters is used. For an aerodynamic analysis, a steady-state, incompressible fluid flow analysis type is employed along with a K-Omega-SST turbulence model. The analysis is carried out on 32 cores and takes nearly 3 hours.
The convergence plot is shown below:
Results and Conclusions
Post-processing for this case is performed locally on ParaView using a custom meshing approach to set-up fluid flow analysis. Mapping the pressure and the velocity streamlines on the car surface helps us better analyze the processes that transpire in real time.
With the goal of increasing the downforce on the car, we analyze the pressure contours. A greater downforce is achieved when the pressure difference between either side of the main spoiler is increased.
Velocity Contours and Streamlines:
A streamline is defined as a line which is everywhere parallel to the velocity vector. The figures below represent the velocity streamlines of the airflow around the F1 car.
To avoid vortex formation, the ends of the spoiler are covered with winglets.Therefore, spoilers with winglets are employed to increase the downforce while reducing the drag force.
Surface Streamlines at mid height: