Highly-Efficient Aerodynamic Optimal Design of Rotor Airfoil Using Viscous Adjoint Method  

作　　者：Wu Qi Zhao Qijun Wang Qing 

机构地区：[1]National Key Laboratory of Science and Technology on Rotorcraft Aeromechanics,Nanjing University of Aeronautics and Astronautics

出　　处：《Transactions of Nanjing University of Aeronautics and Astronautics》2017年第2期134-142,共9页南京航空航天大学学报（英文版）

摘　　要：In order to overcome the efficiency problem of the conventional gradient-based optimal design method,a highly-efficient viscous adjoint-based RANS equations method is applied to the aerodynamic optimal design of hovering rotor airfoil.The C-shaped body-fitted mesh is firstly automatically generated around the airfoil by solving the Poisson equations,and the Navier-Stokes(N-S)equations combined with Spalart-Allmaras(S-A)one-equation turbulence model are used as the governing equations to acquire the reliable flowfield variables.Then,according to multi-constrained characteristics of the optimization of high lift/drag ratio for hovering rotor airfoil,its corresponding adjoint equations,boundary conditions and gradient expressions are newly derived.On these bases,two representative rotor airfoils,NACA0012 airfoil and SC1095 airfoil,are selected as numerical examples to optimize their synthesized aerodynamic characteristics about lift/drag ratio in hover,and better aerodynamic performance of optimal airfoils are obtained compared with the baseline.Furthermore,the new designed rotor with the optimized rotor airfoil has better hover aerodynamic characteristics compared with the baseline rotor.In contrast to the baseline airfoils optimized by the finite difference method,it is demonstrated that the adjoint optimal algorithm itself is practical and highly-efficient for the aerodynamic optimization of hover rotor airfoil.In order to overcome the efficiency problem of the conventional gradient-based opt imal des ign method, a highly-efficient viscous adjoint-based RANS equations method is applied to the aerodynamic optimal design of hovering rotor airfoil. The C-shaped body-fitted mesh is firstly automatically generated around the airfoil by solving the Poisson equations,and the Navier-Stokes （N-S） equations combined with Spalart-Allmaras （S-A） one-equation turbulence model are used as the governing equations to acquire the reliable flowfield variables. Then, according to multi-constrained characteristics of the optimization of high lift/drag ratio for hovering rotor airfoil, its correspond-ing adjoint equations, boundary conditions and gradient expressions are newly derived. On these bases, two representative rotor airfoils, NACA0012 airfoil and SC1095 airfoil, are selected as numerical examples to optimize their synthesized aerodynamic characteristics about lift/drag ratio in hover, and better aerodynamic performance of optimal airfoils are obtained compared with the baseline. Furthermore, the new designed rotor with the optimized rotor airfoil has better hover aerodynamic characteristics compared with the baseline rotor. In contrast to the baseline airfoils optimized by the finite difference method, it is demonstrated that the adjoint optimal algorithm itself is practical and highly-efficient for the aerodynamic optimization of hover rotor airfoil.

关 键 词：rotor airfoil viscous adjoint method aerodynamic characteristics MULTI-CONSTRAINTS computational fluid dynamics(CFD) highly efficiency 

分 类 号：V211.52[航空宇航科学与技术—航空宇航推进理论与工程]