Numerical Study on Laminar Flow Over a Cylinder and Its Rotating Controllers for Suppressing the Vortex Shedding

Vortex shedding exerts the dynamic and periodic forces on cylindrical structures and increasing the FIV and even the resonance. Controlling the flow over the cylinder and delaying the separation, reduces the vortex shedding and achieves the longer lifetime. Among different passive and active methods of flow control, using the flow controllers is a highly practical method. Two small rotating cylinders, near the main cylindrical structure, can be actively used for this purpose. The effects of the geometrical parameters on the oscillatory response of a particular main circular cylinder have been numerically studied for a particular laminar flow regime. The finite volume based on SIMPLE algorithm has been used for simulating the unsteady flow field. The procedure of finding the correct position to controllers is surveyed. The reduction indexes are defined for calculation the effectiveness of controllers. It is shown that there is an optimum position for the proposed condition in which the variation of lift ad drag forces for the cylinder and two rotating controllers are the minimum one and the vortex shedding is suppressed, too. Moreover, the mean drag coefficient is reduced significantly in the prescribed position for the main cylinder and two rotating controllers.