Pressure-Sensitive Paint Application to an Oscillating Shock Wave in a Transonic Flow

Abstract

This paper presents an application of the pressure-sensitive paint technique to investigate two-dimensional unsteady flow in a transonic channel. This work is a contribution to the study of the transonic interaction between an oscillating shock wave and a separated boundary layer in a channel flow. The shock-wave oscillation is forced by the periodic variation of the section of a second throat by means of a rotating elliptical shaft located in its section. The channel’s lower wall is equipped with a contour profile, or bump, allowing for flow separation. To achieve a reduced response time for surface pressure measurements, we use anodized-aluminum coating as pressure-sensitive paint instead of usual paint. An aluminum insert including the bump was manufactured and coated with anodized-aluminum pressure-sensitive paint. Images were acquired by using a high-speed camera, and pressure-sensitive paint results were compared with pressure tap and Kulite sensor measurements implemented in the insert. Spectral analysis was carried out to assess the ability of anodized-aluminum pressure-sensitive paint for understanding unsteady aspects of such a complex channel flow.