Viscous Adjoint Method-based Multi-element Airfoil Optimization Design Study

A viscous adjoint method for aerodynamic optimization using the Navier-stokes equations was studied in this paper. Design examples, including multi-objective optimization for a single-element airfoil, inverse design and the maximal lift design for multi-element airfoil were performed.The main aspects of this paper are as follows:(1) A multi-objective optimization system for a single-element airfoil based on viscous adjoint method was established. The viscous adjoint boundary conditions and gradient formula for multi-objective optimization were derived. The gradient was validated by finite difference method.(2) In order to get the reliable maximal lift of the airfoil, the S-A turbulence model was used in solving Navier-Stokes equations.(3) The Chimera grid technique for solving viscous flow field of the multi-element airfoil was studied.(4) The aerodynamic optimization method for a multi-element airfoil system based on viscous adjoint method was established.(5) The aerodynamic optimization for enhance the maximal lift of the multi-element airfoil was studied.