DETERMINATION OF BOUNDARY-LAYER TRANSITION REYNOLDS NUMBERS BY SURFACE-TEMPERATURE MEASUREMENT OF A 10° CONE IN VARIOUS NACA SUPERSONIC WIND TUNNELS

摘要

An investigation was conducted in the following NACA supersonic wind tunnels to determine transition Reynolds numbers on a 10° cone at zero angle of attack:the 1- by 3-foot (Nos. 1 and 2), the 2- by 2-foot, the 6- by 6-foot, and the 10- by 14-inch at the NACA Ames laboratory;and the 8- by 6-foot, the 2- by 2-foot, the 1- by 1-foot (two), and the 18- by 18-inch at the NACA Lewis laboratory. Measurements of surface temperature at known increments along the cone were made for the case of negligible heat transfer and negligible wind-tunnel pressure gradients. The surface condition of the test body was carefully preserved throughout the program.nThe trends of transition Reynolds number with stream Reynolds number and Mach number are not consistent for the various tunnels. The inconsistencies are attributed to variations in free-stream turbulence, flow irregularities introduced by the compressor systems, and other airstream disturbances such as compression- or expansion-wave boundary-layer interactions.nThe results of this program show that transition Reynolds numbers can be successfully determined by measuring surface temperatures at known increments along a 10° cone, and that the transition Reynolds number is useful for relative evaluation of supersonic facilities.