Adjoint-Based Optimization for Blended-Wing-Body Underwater Gliders' Shape Design

With the wide application of underwater gliders, how to improve the performance of underwater gliders is the research hotspot in various institutions. A large number of efficient shape optimization methods have been proposed for underwater gliders. In this paper, a new adjoint-based optimization frame for shape design of Blended-Wing-Body Underwater Gliders (BWBUGs) is built. Firstly, compared with the traditional gradient-based optimization algorithms, the adjoint method can significantly reduce the cost of computing in obtaining the gradient information process. Then, the free-form deformation (FFD) method is utilized for the geometric parameterization. Mesh deformation is achieved by using a technique based on spring method. Finally, the gradient-based optimization is performed utilizing the SLSQP optimizer. The optimization aims at maximizing the lift-to-drag ratios (LDRs) of BWBUGs in turbulence flow. By comparing the LDR, the optimized shape has an obvious improvement. Furthermore, the whole optimization process is much more efficient than the traditional global optimization.