Simultaneous measurement of surface shape and pressure using structured illumination

This article describes the successful implementation of a structured UV light field, generated from a modified LCD projector, to excite pressure-sensitive paint (PSP) and measure surface shape simultaneously without the need to compromise the PSP by mechanical degradation of the coating. Using commercially available hardware, results were gathered in a Mach 5 wind tunnel, showing the expected pressure distribution around a cone model with a flare and the surface geometry without any prior knowledge or information. The demonstrated methodology can be used to measure aerodynamic models exhibiting elastic deformation under load during a wind tunnel measurement campaign, providing out-of-plane motions are small. The captured deformation and pressure results can be used to support validation of structural models and correct numerical simulation meshes to the actual shape investigated in the wind tunnel.