Coherent Structures of Turbulent Wake Past a Rotating Circular Cylinder with a Tripping Wire

Tripping wire가 부착된 회전원주에 의한 난류휴류의 응집구조

An experimental investigation is conducted to find out the large scale coherent structures in the intermediate wake past a rotating cylinder with a single tripping wire attached. Relation between the vortex shedding frequency and the spin rate of rotating cylinder and the effects of the tripping wire on the flow characteristics were studied by using spectral analysis and conditional phase average technique, respectively. It is found that the vortex shedding frequency is bound to a certain range and varies regularly as spin rate increases. The coherent structures are compared with those of the plain rotating cylinder in the case of spin rate of 1.0. Distance between the upper and lower center of vortices increase and the vortex shedding time is delayed, the velocity fluctuation energy decreases near the center line of vortices and it spreads out to the outer region. The Reynolds shear stress increases highly in the upper region and the turbulent wake width expands with strong entrainment process.