2010 年 5 巻 2 号 p. 331-339
In this study, process of vorticity decay caused by viscous interaction in a separated shear layer was investigated based on velocity measurements and flow visualization in the immediate vicinity of the separation point of a test body. The experiment was carried out at a fixed Reynolds number of 19,000. The research results innovate the important aspects of clarification on vorticity decay including i) part of the vorticity in the separated shear layer behind a body are caused by viscous interaction associated with transition of velocity distribution from boundary layer like shape to free shear layer like shape in the immediate vicinity of the separation point; ii) Reynolds shear stress associated with turbulent diffusion is not concerned in the vorticity decay process in the immediate vicinity of the separation point; iii) since the Reynolds shear stress around an intermediate size vortex produced by pairing of smaller vortices is considerably large, the flow field becomes turbulent and three dimensional.
