mohammadreza barzan

The vortex shedding from a bluff body can provoke structural vibrations known as flow-induced vibrations (FIV), which characterize an intrinsic phenomenon in the design of cylindrical structures. There are numerous passive and active methods to suppress FIV, among which suction and/or blowing on a cylinder surface is one of the most common approaches. In this work, different configurations of simultaneous suction and blowing are considered at two different Reynolds numbers corresponding to the galloping and frequency synchronization ranges. The parameters studied include the number of slots for suction and blowing, their length, and the velocity of the sucked and blown flow. The design of experiments method (DOE) is used to find the required simulation elements. The simulation results show that the dominant parameter in the reduction of galloping and vortex-induced oscillations and mass flow rate is the flow velocity in the areas of blowing and sucking. In addition, regression analysis is used to derive a relationship between various influencing parameters and performance parameters.

Flow-induced instabilities are one of the major challenges in the design of aerospace structures. Numerous passive and active control methods have been used to reduce the flow-induced oscillations of square cross-section cylinder as the basic geometry for structures with sharp corners. The suction and blowing flow control method are one of the most effective approaches for controlling the flow and consequently reducing the vibrations resulting from the aerodynamic forces, which so far are not considered for an elastically-mounted square cylinder which fluctuates freely in the transverse direction. Therefore, in this paper, suction and blowing flow control methods have been used separately to suppress flow-induced oscillations. In the suction-based method, a slut is placed on the front surface of the cylinder and in the blowing-based method another slot is inserted on the back surface of the cylinder. In the present study, the effect of suction and blowing velocities as well as the effect of suction and blowing slut lengths on the efficiency of the flow control approach was evaluated. According to the flow-structure interaction simulations, it is observed that the applied flow control method has been able to reduce flow-induced vibrations appropriately.