Suppression of vortex-induced vibration of a circular cylinder at subcritical Reynolds numbers using shape optimization

In this paper, shape optimization is employed to improve the stability of the flow past an elastically mounted circular cylinder at subcritical Reynolds numbers (Re < 47). As a key criterion for the stability of fluid-structure interaction system, dynamic derivative is adopted as the object of the optimization. The parametrization of the cross section is based on the class-shape function transformation technique. Then, shape optimization is conducted using the differential evolution algorithm. To improve the optimization efficiency, a surrogate model is constructed to replace the direct numerical simulation in the optimization process. Research shows that through the shape optimization, vortex-induced vibration is significantly suppressed and the stability of the fluid-structure interaction system is remarkably improved. In addition, the critical Reynolds number of the optimized cross section is also improved compared with that of the circular cylinder.