PARTICLE IMAGE VELOCIMETRY-BASED MEASUREMENTS OF AN AXISYMMETRIC TURBULENT JET IMPINGING ON A CONCAVE SURFACE

Particle image velocimetry-based measurements for an axisymmetric turbulent jet impinging on a semi-circular concave surface have been undertaken as part of this work. The focus is on studying the ensuing boundary layer formed on the curved surface. The measurements were performed for three different surface curvatures and different distances between the jet and the surface, at a Reynolds number of 23,000. The mean and r.m.s. velocity profiles have been analyzed in detail. The streamwise growth of the boundary layer has also been documented, which shows a nonmonotonic variation. The presence of a large-scale circulation is shown by the data. The measurements also indicate strong lateral movement of the flow brought about by the surface geometry. The magnitude of Reynolds normal and shear stresses are dependent on the surface curvature; their values increase with the surface curvature and remain larger than those for a flat surface. The results indicate mild anisotropy in the boundary layer region. These results can aid in the interpretation of heat/mass transfer data from a concave surface and can also serve as benchmark data for future numerical studies.