| Popis: |
This paper describes an experimental study on the internal structure of the Mach 4 pseudo-shock wave (PSW) in a straight square duct with cross section of 80×80 mm^2, using the new Mach 4 supersonic wind tunnel of Muroran Institute of Technology. The free stream Mach number, unit Reynolds number, and flow-confinement just upstream of the PSW were M_∞=3.98, Re=2.6×10^7 m_, and δ_∞/h=0.39, respectively, where δ_∞ is the boundary layer thickness, and h is the half height of duct. The development and characteristics of the turbulent boundary layer on the top and bottom walls of the duct was investigated by LDV measurements. The internal structure of the Mach 4 PSW was clarified by color schlieren photographs and Particle Image Velocimetry (PIV) measurements. It reveals that the turbulent boundary layer on the top or bottom wall of the duct separates in large just after the first oblique shock of the PSW, and the internal flow with the PSW becomes asymmetric flow. |
