Aerodynamic shape optimization design of civil jet wing-body-tail configuration

The approach of applying discrete adjoint technique-based aerodynamic shape optimization on civil jet wing-body-tail configuration has been presented, in which free-form deform (FFD) technique has been used to rotate the tail for trimming the whole aircraft. Reynolds-averaged Navier-Stokes (RANS) equations solver has been used for simulation together with a discrete adjoint solver for computing the gradients of the objective function with respect to the design variables, which makes the computational cost almost independent from 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 to handle large number of constraints. Drag prediction workshop IV common research model has been used as the baseline configuration, on which design optimization for drag reduction with and without the trimming constraint has been researched. The results of the optimization cases show that the shock wave on the wing could be fully eliminated after the optimization and the drag has been reduced. In the case with trimming constraint, the pitching moment is trimmed by a rotation angle of the tail by the optimizer.