Pressure Loss Reduction of a Radial Supersonic Internal Flow.

Thi paper describes the experimental study of the radial supersonic flow behavior over the riblet surface mounted on the disk-shaped wall to reduce a pressure loss. The experiments have been performed in an indraft supersonic wind tunnel installed with disk-shaped channel at Mach numbers ranging from 1.8 to 3.3 just in front of a pressure rise. The static pressure rise in the pseudo-shock region observed in a channel with riblet surface became milder than that for the case of smooth surface, and significance of its difference was indicated by uncertainty analysis entimated at 95% coverage. The contours of stagnation pressure obtained by traversing a Pitot-tube showed that a higher stagnation pressure was maintained near the riblet surface compared with that for the smooth surface. Furthermore, it was found that the stagnation pressure loss reduced about 20% near the riblet surface at a Mach number of 2.5.