AirShaper

[aerohead]

here's some limited data on CFD vs full-scale tunnel testing
https://airshaper.com/blog/tesla-mod...c-benchmarking

[freebeard]

Thanks. I'm curious as to how they got the scan of the underside of the Model Y.

It's also interesting that the scan couldn't find the bottom of the door gaps. They had to manually create what's called a 'watertight manifold'.

[aerohead]

Me too!
Could be that they actually did a 3D-laser scan of the actual car, as input for the CFD software.
A research university in China previously published a CFD analysis for the Tesla Model S, and I believe that they did scan an actual car to get the data cloud.
A college mate, with aeronautical engineering degree from NASA, worked at Southwest Research Institute in San Antonio, Texas. They had a physical, 3D scanning device Glynn used to scan an US NAVY F-4 Phantom jet, then used to operate a walnut shell blasting media paint removal device which 'knew' where the aircraft 'was', incorporating optical recognition software, to ascertain 'when' the paint was satisfactorily removed.
If a car was mounted on a rotisserie, giving the physical probe access the underbody, it wouldn't be a problem to 'learn' the whole car.
It would take a long time though.

[freebeard]

A rotisserie is an uncommon item but they exist in body shops.



My thought was throw some straps through the window openings and lift it with a crane. But smart phone photogrammetry stitches together multiple pictures so it might have been done on a lift.

[Piotrsko]

Wouldn't you only need to have the scanner head be under the vehicle? Couple of cinderblocks under the tires should suffice or use mirrors to reflect the laser. Afaik, it is the RELATIVE distances that generate the dimensions, not the total distance.

[Vekke]

They have cooperation with a2mac1 who scan the vehicles and do full teardown for all cars. You can buy the scan file, reports conserning performance, manufacturing etc and comparisons to other vehicles etc. Airshaper then does simulations to that scan cloud. models are simplified to certain level depending what you want to study.

[freebeard]

For the lurkers: duckduckgo.com/?q=a2mac1