Aerodynamic shape optimization of aircraft configurations often ignores stability considerations. To address this, a method for the computation of static, dynamic, and transient aircraft stability derivatives and their sensitivities for use in gradient-based optimization is introduced and evaluated. Computational fluid dynamics in the form of a three-dimensional, structured-grid, multi-block flow solver with both Euler and Reynolds-averaged Navier--Stokes equations is used. To compute the stability derivatives, a time-spectral formulation is used to compute an oscillating solution for the configuration of interest. From this oscillating solution, a series of linear regressions is performed to calculate the various stability derivatives. Because the solution is time-dependent, it contains the information required to compute the transient---or {\textquoteleft}{\textquoteleft}dot{\textquoteright}{\textquoteright}---derivatives for the configuration. An adjoint method is used to compute the gradients of the stability derivatives of interest, enabling gradient-based stability-constrained aerodynamic shape optimization with respect to a large number of design variables. The computed stability derivatives are verified for an airfoil, and validated for the Stability and Control Configuration unmanned aerial vehicle. The stability-constrained optimization of a wing demonstrates the viability and usefulness of the method for aircraft design optimization.

}, doi = {10.2514/1.J052922}, author = {Charles A. Mader and Joaquim R. R. A. Martins} }