Experimental Investigation of the Aerodynamics of Independently RotatingCylindrical Shells

摘要

The purpose of this thesis was to investigate experimentally the aerodynamicforces on two adjacent, independently rotating cylinders in a cross-flow. This investigation involved a force measurement setup which had the two cylinders mounted on a common support shaft, extending beyond the span of the wind tunnel test section, and supported by spoke rings with strain gages in the vertical and horizontal directions. This setup proved capable of measuring aerodynamic forces. The lift on the independently rotating cylinders was found to increase as one cylinder's angular speed increased while the other's remained constant, and decrease as the relative angular rate decreased. The drag coefficient was fairly constant over the range of velocity ratios tested, and minimal changes were noted with relative changes in angular speeds. Interactions between the two cylinders had the most effect on the lift and drag above 40% disparity in the angular rotation rates. The investigation also showed that for an offset angle of 30 deg on an approximately two-dimensional cylinder, the normal component of freestream velocity may be treated as the only significant contributor to the forces on the cylinder.... Rotating Cylinders, Lift, Drag, Velocity Ratio.