Dr. Rubén Sánchez Fernández, SciComp

Title:
A Coupled Adjoint-Based Method for Aeroelastic Design in the Open-Source SU2 Suite

Abstract:

Computational Fluid-Structure Interaction (FSI) methods have reached a significant level of maturity, which has led to their incorporation into the analysis stage of industrial applications. However, optimising the structural and/or the aerodynamic performance in highly non-linear coupled FSI problems remains a challenging task, due to the high computational cost of evaluating the objective functions in this problem and their gradients. Adjoint methods have shown to be an efficient methodology for this latter task, as they can compute sensitivities with a computational cost independent of the number of design variables. On the other hand, their implementation is complex, particularly when the linearisation of the system equations is convoluted.
A novel technique for the evaluation of the coupled adjoint problem for FSI is presented. It is based on the consistent application of Algorithmic Differentiation to the fixed-point iterators of the subproblems. This approach makes the computation of the adjoint independent from the solution methods employed for the primal problem, and overcomes the usual limitation for most realistic applications, which is the need for an explicit construction of the analytic Jacobian of the coupled problem. The method poses no restrictions to the non-linearity of the physics in either the fluid or structural field, and it is amenable to partitioned solution methods for the primal and adjoint FSI problems.