Abstract: The approach of applying discrete adjoint technique based aerodynamic shape optimization on civil jet wing-body-tail configuration has been presented, in which FFD technique has been used to rotating the tail for trimming the whole air-craft. Reynolds-Averaged NS equations solver has been used for simulation together with a discrete adjoint solver for computing the gradients of the objective function respect to the design variables, which makes the computational cost almost independent to the number of design variables. FFD technique has been used for all-at-once parameterization of the wing shape and the tail, so that the wing shape and the tail rotation could be controlled simultaneously, which could trim the aircraft as a moment constraint while optimizing the wing and avoid the trim drag when optimizing the wing only. Sequential quadratic programming has been used for gradient based optimization handling large number of con-straints. Drag Prediction Workshop-4 Common Research Model has been used as baseline model, on which design opti-mization for drag reduction with and without the trimming constraint has been researched. The result of the optimization cases show that, the shock wave on the wing could be fully eliminated after the optimization, and the drag has been re-duced. In the case with trimming constraint, the final design is trimmed by a rotation angle of the tail by the optimizer.

Key words: aerodynamic optimization, wing design, trimming, discrete adjoint, free-form deform (FFD)