Question: At which point (in measurements of speed) does air friction start heating instead of cooling?

At which point (in measurements of speed) does air friction start heating instead of cooling?

Everyone has seen the windchill chart, showing how air speed will lower the air temperature around a moving object. BUT... if that windchill chart was taken to the extremes in airspeed, at what point would the temperature start an upward trend? I know that the aerodynamic "fingerprint" of an object would be a huge factor in this (i.e., a javelin would have to travel much faster than a tour bus), but there should be an approximate value. Thanks!

Date Posted: October 25, 2007 Tagged Under: aerodynamics . astrophysics