For Zoom Link please contact ddelreyfernandez@uwaterloo.ca

## Speaker

Professor Krzysztof Fidkowski , University of Michigan, Department of Aerospace Engineering

## Title

Adjoint-based Adaptation and Optimization of Unsteady Turbulent Flows using Dynamic Closures

## Abstract

We present a data-driven approach for calculating adjoint sensitivities in unsteady turbulent flows, with application to shape optimization and output-based adaptation. The approach does not use unsteady adjoint equations, which are expensive to solve and become unstable for chaotic problems, but instead relies on unsteady data to train a corrected turbulence model, i.e. a dynamic closure, which then yields the required adjoint solutions. It is non-intrusive and inexpensive, requiring only a small number of unsteady forward simulations, but sufficiently powerful to capture unsteady effects in the sensitivities. Results for high-order discretizations of the unsteady Navier-Stokes equations, augmented by a corrected Spalart-Allmaras turbulence closure, demonstrate the ability of the approach in driving airfoil shape optimization and in adapting unsteady flowfields to target statistical outputs of interest.