A review of Reynolds number studies conducted in the Langley 0.3-m Transonic Cryogenic Tunnel

Initial proof-of-concept results obtained in a pilot transonic tunnel, led to a U.S. decision to apply the cryogenic tunnel concept to the National Transonic Facility (NTF). The pilot tunnel was reclassified as a 'permanent' facility and renamed the 0.3-m Transonic Cryogenic Tunnel (TCT). The 0.3-m TCT, with its ability to operate at temperatures ranging from about 78 K to 340 K, combined with a 6 atmospheres pressure capability, provides extremely high test Reynolds numbers at relatively low model loading. In addition, the ability to vary pressure and temperature independently of Mach number provides a unique capability to conduct studies at a constant dynamic pressure or at a constant Reynolds number with just one model. Attention is given to the simulation of flight conditions, the cryogenic-pressure tunnel concept, the characteristics of the 0.3-m TCT, Reynolds number studies in the three-dimensional test section including a Space Shuttle study, and Reynolds number studies in the two-dimensional test section.