Experimental Works in the NAL High Reynolds Number Two-Dimensional Transonic Wind Tunnel on Advanced Technology and NACA Airfoils

摘要

A description of a new wind tunnel at NAL and some results of initial calibration and tests of new transonic airfoils are presented. In order to test the new transonic airfoils at high Reynolds number, a two dimensional transonic pressure wind tunnel at NAL, Japan was constructed in 1979. This blowdown type wind tunnel has a 0.3 meter wide and 1.0 meter high test section. The performance is 0.2 to 1.15 of Mach number range and 40 x 10 to the 6th power of maximum Reynolds number with 10 seconds running time. The wind tunnel starting operation is conducted with precharged air in the tunnel. Closed loop Mach number control is successively applied with excellent regulation and repeatability. Results of the initial calibration indicate adequate performance of the tunnel. The conventional airfoil data are compared with other published experimental results. The Reynolds number effects on the aerodynamic characteristics of NACA 0012 section were experimentally investigated. A few transonic airfoils which were developed at NAL were tested and compared with theoretical and numerical results. Comparisons demonstrated good correspondence in some cases as well as gross discrepancies in other cases and those suggest the importance of experimental works.