Shape Optimization of Blended-Wing-Body Underwater Gliders Based on Free-Form Deformation

基于FFD的翼身融合水下滑翔机外形优化设计

School of Marine Science and Technology, Northwestern Polytechnical University, Xi'an 710002, China

Received: 30 August 2019

Abstract

Currently developed underwater gliders can be roughly divided into the two types:traditional configuration and unconventional configuration. As a type of underwater gliders with unconventional configuration, a blended-wing-body (BWB) underwater glider has better fluid dynamic performances because of its unique shape. However, it is difficult to design the shape of the BWB underwater glider that has excellent hydrodynamic performances. Therefore, it is of great significance to optimize its shape, which this paper carries out by using the free-form deformation (FFD). The complete and automatic shape optimization framework is established by jointly using FFD parameterization method, CFD solver, optimization algorithm and mesh deformation method. The framework is used to optimize the shape of a BWB underwater glider. The average drag coefficient of the BWB underwater glider during its sinking and floating in one working period is used as the objective function to optimize its shape, with the volume constraints considered. The optimization results show that the gliding performance of the BWB underwater glider is remarkably enhanced.

摘要

水下滑翔机发展至今大体上可以分成2个大类：常规布局外形水下滑翔机与非常规布局水下滑翔机。翼身融合水下滑翔机作为一种非常规布局水下滑翔机，因其独特的流体外形布局，具有更好的流体动力特性。但设计出具有优秀水动力性能的翼身融合水下滑翔机外形较为困难，因此开展翼身融合水下滑翔机外形优化设计研究工作具有十分重要的意义。开展基于自由变形(FFD)的翼身融合水下滑翔机外形优化设计研究，以FFD参数化方法为核心，与CFD求解器、优化算法、网格变形方法相耦合，组成了完整的自动外形优化设计框架，并用该框架开展了翼身融合水下滑翔机外形优化设计工作。以翼身融合水下滑翔机下沉和上浮一个工作周期的平均阻力系数为目标函数，在考虑体积约束的条件下开展外形优化设计，优化结果表明翼身融合水下滑翔机的滑翔性能得到了明显提升。