INITIAL CALIBRATION RESULTS FROM THE AEDC-PWT 4-FOOT TRANSONIC TUNNEL

Abstract : Tests were conducted in the AEDC Aerodynamic Wind Tunnel, Transonic (4T), to determine the tunnel calibration, Mach number distributions, and boundary-layer thicknesses. During the tests, Mach number was varied from 0.1 to 1.4, test section wall angle from -0.5 to 0.5 deg, and test section wall porosity from 0 to 10 percent. Data were obtained at various stagnation pressure levels from 500 to 2500 psf. Considerable development of the flow expansion region was required to obtain uniform supersonic Mach number distributions. Good Mach number distributions are obtainable up to and including Mach number 1.2. The distributions from Mach number 1.25 to 1.4 are suitable only for very limited testing. The results show that the tunnel calibration is a function of test section wall porosity and wall angle. Boundary-layer thicknesses on the contoured walls and parallel walls at the nozzle exit are nearly equal.