Hydrodynamic characteristics of flow past a circular cylinder with four attached flexible plates in a high Reynolds number turbulent flow

Abstract

In this study, the $k-\omega SST$ model is employed to evaluate the effects of flexible plates on the hydrodynamic forces acting on a circular cylinder in turbulent flows. In this regard, four flexible plates are attached to the circular cylinder. Besides, the finite volume method and finite element method have been utilized to discretize the governing equations of the fluid flow and the flexible plates, respectively. The Reynolds number based on the cylinder diameter is kept constant at $Re={10}^5$ . The effects of fin angle $\left(\theta =0^{\text{°}}\text{ and }\hspace{0.17em}{45}^{\text{°}}\right)$ and the flexural rigidity $\left(3 \le E{I}^{\ast } \le 20\right)$ on the wake structure, displacement amplitude, Strouhal number as well as lift and drag coefficients are investigated. The results showed that the flexural rigidity of plates had a significant influence on the hydrodynamic coefficients. Indeed, an increase in the non-dimensional flexural rigidity enhanced the drag coefficient, and then it approximately remained constant. For $\theta =0^{\text{°}}and E{I}^{\ast }\le 5,$ the averaged drag coefficient is approximately constant and equal to 6.1. As the $E{I}^{\ast }$ increases, the drag coefficient increases rapidly and reaches the value of 14.37 for $E{I}^{\ast }=20.$ In the second configuration $\left(\theta ={45}^o\right)$ , values of the drag coefficient for low $\left(E{I}^{\ast }=5.33\right)$ and high $\left(E{I}^{\ast }=20\right)$ values of flexural rigidity are equal to 7.81 and 8.79, respectively.