Vehicle spoiler and diffuser
Changing a spoiler angle by one degree changes downforce and drag together. Which way and by how much is not knowable without running it.
The decision
How much drag is this spoiler angle costing for the downforce it buys.
Setting it up
- Take the outer shell as STL; leaving mirrors and wheel detail out of the first pass makes the run quicker
- Change the angle and export each variant as its own STL
- Keep the speed fixed, so you are the only one changing a variable
- Include the ground plane if the flow underneath matters
What you see
- The pressure difference between the upper and lower surfaces
- Whether the flow separates at the diffuser exit
- Live CL and CD, compared directly between variants
The awkward part
On a road car the rotating wheels and the moving ground are real effects, and a run like this does not represent them. Read the results as the difference between variants, not as absolute numbers.
The limit
This is a design-stage tool. Use it to compare shapes against each other and to catch obvious mistakes. For a number that goes to certification, approval or a signature, take the chosen shape to a validated solver or a wind tunnel.
Other analyses
Try it with your own file
Free during the beta. Request a key by e-mail and install it on a Mac running macOS 14 or later on Apple Silicon.
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