A new and effective method of multi-objective drag reduction with fixed angle of attack based on adjoint equation

Aim. The introduction of the full paper discusses relevant matters and then proposes the drag reduction method mentioned in the title, which we believe is new and effective and which is explained in sections 1 and 2. Their core consists of: "Using adjoint-based gradient optimization method, we present a new method for multi-objective drag reduction, which keeps the lift fixed without the need of adjusting the angle of attack. The constraint of fixed lift is included in the objective function, and the variation of the lift is introduced into the adjoint equation boundary conditions. " We present two drag reduction designs respectively of S73613 and RAE2822. The calculated design results, presented in Figs. 1 through 4, and their analysis show preliminarily that our design method is indeed valid and effective.