Tire Aerodynamics

[manta22]

Maybe this has been rehashed here before but ... if a streamliner is traveling at 400mph, the top of its tires are traveling forward at 800 mph- well into the supersonic region. I remember seeing a very interesting film back in college that was produced by Shellr Oil Company about transonic flight. It had wind tunnel Schlieren images of shock wave buildup that were very graphic. I wonder if tires form a shock wave and possibly distort at high speed?

[tortoise]

Maybe this has been rehashed here before but ... if a streamliner is traveling at 400mph, the top of its tires are traveling forward at 800 mph- well into the supersonic region.

But they aren't traveling 800 mph relative to the air inside the wheel well. It's the relative velocity that counts. A Mach 0.5 lakester would be another matter.