Truck air deflector
On a long run, drag is fuel. How the gap between the cab and the trailer is closed matters as much as the height of the deflector on the roof.
The decision
Is this deflector height actually steering the flow over the gap.
Setting it up
- Model the cab and the trailer as one body, with the gap between them
- Set the motorway speed, and try a few degrees of yaw to see the crosswind case
- Change the deflector height and run each one
What you see
- Pressure on the trailer's front face, which drops if the deflector is working
- Streamlines through the gap
- Live CD as the height changes
The awkward part
There is crosswind on a real road, all the time, and a single run at zero yaw will not show it. Add at least one yaw angle.
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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