| Experimental investigations were carried out for flow past a sphere in a closed circuit wind tunnel. Two different sets of experiments were carried out. In the first case, the sphere was supported by a rod. The sphere was made of polymer material and had a diameter of 102 mm. Freestream turbulence was generated by placing a perforated plate at the entrance of the test section. The Reynolds number of the flow, based on the diameter of the sphere ( d), was set at 3.3 x 104, 5 x 10 4 and 6.6 x 104 by varying the mean flow velocity. In the second set of experiments, the sphere was supported by strings. This sphere was also made of polymer material and had a diameter of 102 mm. Three different perforated plates, having holes of size 25 mm, 37.5 mm and 50 mm were used. The Reynolds number of the flow was kept constant at 5 x 104.;The results from the analysis of the vortex shedding process clearly showed that the strength of the shedding signal weakens in the presence of the freestream turbulence. Energy dissipation rate and rms velocity showed an increasing trend with increase in Reynolds number. The peak value of Reynolds stress decreased with increase in integral length scale. (Abstract shortened by UMI.)... |
