Global Visualization of Compressible Swept Convex-Corner Flow Using Pressure-Sensitive Paint

Kung-Ming Chung,Yi-Xuan Huang

doi:10.3390/aerospace8040106

Abstract

This study used pressure-sensitive paint (PSP) and determined the surface pressure distributions for a compressible swept convex-corner flow. The freestream Mach numbers were 0.64 and 0.83. The convex-corner angle and swept angle were, respectively, 10–17° and 5–15°. Expansion and compression near the corner apex were clearly visualized. For the test case of shock-induced boundary layer separation, there were greater spanwise pressure gradient and curved shocks. The acquired PSP data agree with the experimental data measured using the Kulite pressure transducers for a subsonic expansion flow. For a transonic expansion flow, the discrepancy was significant. The assumption of a constant recovery factor is not valid in the separation region, and temperature correction for PSP measurements is required.

Highlights

Swept Convex-Corner Flow UsingPrandtl–Meyer expansion in supersonic and hypersonic flows is well known [1,2].In subsonic and transonic flows, variable camber control using deflected control surfaces can be used to maximize the lift-to-drag ratio in different flight conditions [3]
For a swept convex corner, Chung and Su [6] showed that an increase in the swept angle, λ, results in a delay in the transition from subsonic to transonic expansion flow and in shock-induced boundary layer separation (SIBLS)
For a swept convex-corner flow at M = 0.64, this was in the subsonic flow regime

Summary

Introduction

Swept Convex-Corner Flow UsingPrandtl–Meyer expansion in supersonic and hypersonic flows is well known [1,2].In subsonic and transonic flows, variable camber control using deflected control surfaces can be used to maximize the lift-to-drag ratio in different flight conditions [3]. The peak value of surface pressure fluctuations reaches approximately 15% of the local mean surface pressure [5]. For a swept convex corner, Chung and Su [6] showed that an increase in the swept angle, λ, results in a delay in the transition from subsonic to transonic expansion flow and in SIBLS. The shock excursion phenomenon is alleviated, resulting in reduced peak pressure fluctuations. The value of the Strouhal number increases slightly with an increasing local peak Mach number, Mp , and approaches that of an unswept convex-corner flow.

Methods

Results

Conclusion