Image Measurements of Oscillating Shock Wave by Anodized Aluminum PSP

Abstract

This paper presents an application of the Pressure Sensitive Paint (PSP) technique to investigate two-dimensional unsteady flow in a tran sonic channel. This work takes place in the study of the transonic interaction between an o scillating shock-wave and a separated boundary layer in a channel flow. Oscillation of th e shock-wave is forced thanks to a periodic variation of the downstream throat section given by a rotating elliptical shaft located near this throat inducing pressure perturba tions moving upstream. The channel’s lower wall is equipped with a contour profile ‐ or a bump ‐ allowing for flow separation. In order to achieve reduced response time, we use Anodized-Aluminum coating as PSP (AAPSP) instead of usual paint. Thus, an aluminum insert including the bump has been manufactured in the contour profile and coated with AA-PSP. Images are acquired by using a fast frame rate camera and PSP results are compared with pressure tap and Kulite sensor measurements implemented in the insert. Spectral analysis have been carried out to assess the ability of AA-PSP for understanding unsteady aspects of the flow against unsteady pressure sensors.