Abstract
Omnidirectional reductions in drag and fluctuating forces were investigated for a circular cylinder subjected to cross-flow by attaching spherical rings along its span at an interval of several diameters. The Reynolds number based on the diameter of the circular cylinder, Red, ranged from 10000 to 38000. In this work, the effects of ring configuration, the diameter D and spanwise pitch P, was investigated at D/d = 2.0 and 1.45, and P/d= 2.25 -・6. As a result, it was found that the drag coefficient was reduced by 10-12 % at D/d = 2.0 for Re_d = 38000. In this case, periodicity in the pressure fluctuation on the sides of the cylinder was much reduced, especially for P/d≒3. This indicates that the vortex shedding was suppressed effectively at this condition.
