Vortex Shedding from a Circular Cylinder Placed in a Turbulent Wall Jet

Vortex shedding from a circular placed in a plane wall jet was estimated by measuring the fluctuating velocity component with hot-wire anemometer which was positioned in a wake behind the cylinder. Spectral analysis of hot-wire signals demonstrated that regular vortex shedding from the cylinder was appeared when the location of the cylinder axis was greater than 0.75 cylinder diameters, but that it became decayed gradually when the distance between the cylinder axis and the wall was greater than 80mm. The Strouhal number was decreased by effect of the velocity gradient and exhibited lower value compared with the result of which the cylinder was placed in uniform flow. Approaching velocity of the lower side of the cylinder was adopted as the characteristic velocity in the formula of the Strouhal number and these results showed agreement with that of the cylinder in uniform flow. Spanwise scales of the shedding vortices were estimated from the integral length scale and these were almost close to the cylinder diameter.