Boundary Layer Fence Method for Measuring Surface Shear Stress in a Supersonic,High Reynolds Number Flow Field.

摘要

Experimental research on a boundary layer fence technique was conducted in the Air Force Flight Dynamics Laboratory's M=3 high Reynolds number wind tunnel. The purpose of the research was to develop this particular technique for measuring the surface shear stress in a supersonic compressible turbulent boundary with near adiabatic wall condition and zero pressure gradient. The measurements were made on the tunnel wall at a nominal Mach number of three. The Reynolds number was changed by two methods, i.e., changing the tunnel stagnation pressure and the measuring station. The resulting momentum thickness Reynolds number varied from 20,000 to approximately 540,000. The recorded measurements were (a) the surface shear stress, (b) the Preston pressures, and (c) the pressures ahead and behind the boundary layer fence. The corresponding skin friction coefficients were compared with each other and the Van Driest II theory. The skin friction coefficients obtained with the fence agreed reasonably well with those obtained with a balance and the Preston tube. The skin friction coefficients from all three techniques agreed very well with the Van Driest II theory. (Author)