Measurement of the continuous pressure and surface shear stress vector distributions beneath an inclined, impinging jet using coating and imaging techniques

The pressure-sensitive paint (PSP) method and the shear-sensitive liquid crystal coating (LCC) method were separately applied to measure the areal pressure and shear stress vector distributions on a planar test surface beneath an inclined, axisymmetric, turbulent impinging jet. The combined results provide the first-ever consolidated measurements of the continuous normal and tangential force distributions beneath a fundamental flow field. Present results indicate that the PSP method can be extended to the measurement of small pressure differences (<~0.1 psig) encountered in low-speed flows. Further, these results provide the first demonstration of the capability of the LCC method to measure continuous surface shear stress vector distributions on planar surfaces where shear vectors of all possible orientations are present.