Interaction of two parallel free oscillating flat plates and VIV of an upstream circular cylinder in laminar flow

Flow-induced vibration of bluff bodies and especially circular cylinders have been always of great interest and flat plates are known as useful means for altering flow structure to the desired condition. This work aims to investigate the effect of two parallel downstream flat plates which are mounted in the wake of a circular cylinder. Different configurations including eight horizontal (0.5≤G ≤ 4) and two vertical gaps (H = 0.5, 1) are numerically simulated to focus on the near wake structure and FIV of objects. The results show that the response of parallel plates in the wake of a stationary cylinder depends on both their horizontal and vertical locations. Change in the vertical distance alters the vortex shedding suppression mechanism. While a smaller vertical distance leads to a larger horizontal non-oscillating range, it comes with a higher maximum vibration amplitude. In the case of simultaneous oscillation, all three objects vibrate in all horizontal distances for the smaller vertical gap. The vibration disappears for the larger gap due to weaker interaction between the plates and the shear layers for a range of horizontal distances. The higher vibration amplitude in simultaneous vibration shows the considerable potential of the current concept for developing an improved energy harvesting system.