Using cryogenic Temperature-Sensitive Paint (cryoTSP) as a tool for transition detection

Abstract

Simulating true flight Reynolds numbers with scaled models requires the use of cryogenic wind tunnels. Transition detection in ‘warm’ wind tunnels can be realized using commercially available IR cameras. In cryogenic testing, IR imaging becomes more difficult because of the reduction in radiated energy and the shift to longer wavelengths. At low cryogenic temperatures (say T = 110K) it is nearly impossible to get any meaningful results, also when using helium cooled (very sophisticated) IR cameras. On the other hand, custom-built temperature sensitive paint for cryogenic testing (cryoTSP) still works well for the purpose of transition detection at low temperatures on a wind tunnel model.