MEASUREMENT OF CONTINUOUS PRESSURE AND SHEAR DISTRIBUTIONS USING COATING AND IMAGING TECHNIQUES

The pressure-sensitive paint (PSP) method and the shear-sensitive liqu id crystal coating (SSLCC) method were sequentially applied to measure the areal pressure and shear stress vector distributions on a planar test surface beneath an inclined, axisymmetric, turbulent impinging je t. The combined results provide the first-ever consolidated measuremen ts of the continuous normal and tangential force distributions beneath a fundamental flowfield. Results indicate that the PSP method can be extended to the measurement of small pressure differences (< similar t o 0.1 psig) encountered in low-speed atmospheric flows. Further, these results provide the first demonstration of the capability of the SSLC C method to measure continuous shear stress vector distributions on pl anar surfaces beneath flowfields where shear vectors of all possible o rientations are present.