High-Order FSI for Large-Deformation Aeroelastic Simulations

Student : Braden Frigoletto

Sponsor : Air Force Research Laboratory (AFRL)


Braden’s research is involved in the development of an adaptive, high-order fluid-structure interaction (FSI) solver for large-deformation aeroelastic simulations. The first major milestone in this work involves the demonstration of high-fidelity coupled FSI simulations, after which, numerical errors on aeroelastic outputs will be estimated using coupled adjoints. These error estimates will be fed to mesh adaptation algorithms for both fluid and structural discretizations, adapting using either h or p methods. It is believed that coupled hp-adaptivity will lead to drastically-faster convergence in aeroelastic outputs of interest, requiring far fewer degrees of freedom compared to uniform refinement of fluid and structural domains. This can potentially reduce  analysis time during the detailed design and analysis portion of the design cycle for flexible and very flexible aircraft. Experimental validation of the simulation results will be conducted via wind tunnel testing in Michigan’s low-turbulence 5-by-7 foot wind tunnel. These experiments will utilize the pitch-and-plunge apparatus (PaPA) developed by A2SRL. PaPA allows models to fly with pitch and plunge rigid body degrees of freedom in free/free, locked/free, free/locked, and locked/locked configurations.

Braden’s responsibilities for this project include the handling of the structures portion of the code within the FSI solver and the coupling with the fluids portion of the solver. Braden also leads the effort in the experimental validation of the numerical work. The structural FEM code selected for the project is the Toolkit for the Analysis of Composite Structures (TACS)[1]. TACS is a parallel finite element code for analysis and gradient-based design of advanced structures and was developed by Prof. Graeme Kennedy of Georgia Tech[2]. TACS will be coupled with xflow, a fluids solver developed by Prof. Krzysztof Fidkowski’s group[3] at the University of Michigan. Currently, Braden is involved in the validation of the data acquisition techniques planned for use with PaPA and with future models that will be used for generating data to be compared with the coupled FSI solver results. Currently, TACS and xflow are being coupled together, and in the coming months, the first coupled simulations will be conducted.

[1] https://github.com/gjkennedy/tacs

[2] https://ae.gatech.edu/people/graeme-james-kennedy

[3] https://aero.engin.umich.edu/people/krzysztof-fidkowski/