Shape optimization and hydrodynamic simulation of a Magnus anti-rolling device based on fully parametric modeling
Jianfeng Lin, Hua-Dong Yao, Yang Han, Yumin Su, Chengsen Zhang
Abstract
Ship anti-rolling devices are an essential component of modern vessels. The core component of the Magnus effect-based ship anti-rolling device is a rotating cylinder, hereinafter referred to as the Magnus cylinders. In this paper, fully parametric three-dimensional modeling of Magnus cylinders was performed, and the design space dimension was reduced using the Sobol design optimization method while still providing accurate and reliable results. The Sobol method generates quasi-random sequences that are more uniformly spaced in the search space and can more efficiently cover the entire solution space. The shape optimization study of the Magnus cylinder was carried out in conjunction with the computational fluid dynamics method to find the geometry of the Magnus cylinder with excellent hydrodynamic performance. Critical design parameters include the diameters of the cylinder ends and the length of the cylinder. The hydrodynamic and flow field characteristics of Magnus cylinders before and after the optimization were compared. The results show that there can be multiple local optimal values for lift and drag of Magnus cylinders within the design space to increase the lift and decrease the drag. The Magnus effect primarily influences the position of the vortex-shedding separation point at the surface of Magnus cylinders and deflects the wake to one side. For the optimized Magnus cylinder, the distribution of pressure and velocity in the flow field is significantly different. This research forms the basis for improving the practical application of Magnus anti-rolling devices.