Abstract
The effects of end wall conditions and aspect ratios on the surface pressure and the local drag coefficients of a circular cylinder were examined experimentally at blockage ratio 3% and Reynolds number 8000. Both end walls supporting the cylinder were the flat plates with different tip conditions on which two-dimensional transition boundary layers were formed. The ratio of boundary layer thickness to cylinder diameter at the cylinder position was 0.60 or 0.83, and the aspect ratio was varied from 8 to 32. In the case of thick wall boundary layer, the base pressure coefficient along the cylinder axis was almost constant for all aspect ratios except in the vicinity of the end wall, but rapidly rose with decreasing the aspect ratio. In the case of thin wall boundary layer, the base pressure coefficient was little constant along the cylinder axis, but the difference for various aspect ratios is relatively small.
