Characteristics of the Flow around a Bluff Body near a Plane Surface

抄録

The characteristics of the flow around a normal flat plate and a triangular cylinder near a plane surface has been investigated experimentally in the Reynolds number range of 10²to 3×10⁴. Frequency analysis of hot wire signal of the wake flow in a wind tunnel revealed that regular vortex shedding from the normal flat plate and the triangular cylinder was suppressed for spaces less than about 0.6 and 0.37 times the body width respectively. Investigation of the time-mean distance between two shear layers in the vortex formation region demonstrated that the suppression of vortex shedding for both configurations occurred for any space between the inner shear layer and the plane surface less than about 0.3 times the shear Iayer distance. Flow visualization experiments in a water tank revealed the structural differences of the wakes with and without vortex shedding.