Transient Euler Analysis of a Race Car
In this example, we will demonstrate a simple external aerodynamic flow analysis of a race car. We seek to evaluate the time-averaged forces about the car geometry. Specifically, we are interested in evaluating the down force produced, as increasing this downforce allows drivers to power through corners faster and more safely.
We will be solving the time-dependent Euler equations. An advantage of running a fully transient analysis is twofold. First, transient solvers are more robust than steady-state solvers, as a steady-state solution may not exist. Second, it provides better insight into the physics of the simulation, as temporal terms are not neglected.
To begin, import the STL geometry representing the car surface using the "Run Example” button below. This will automatically start a simulation, with a freestream value of unity in the x-direction. The status of the simulation will be displayed in your solver console. To view the STL file, click on the name of the file, in this case racecar.stl.
Figure 1 Race car STL surface to ba evaluated using the transient Euler solver.
If we now go back to the solver console, we can check on the status of the case by clicking on “details”. This will take you to the case console. Once the mesh has been generated, the surface pressure and force history will be streamed to the case console in real-time.
Figure 2 a) Force history and b) pressure distribution showing vorticies due to separated flow.
Specific regions of the force history can be zoomed in to using the slide bar below the force graph. Additionally, race car surface may be manipulated to identify significant regions of vortex shedding.