Analysis and Design Tools for Fluid-Structure Interaction with Multi-Body Flexible Structures

The overall objective of this proposal (Phases I and II) is to develop a robust and accurate solver for fluid-structure interaction computations capable of addressing multi-body flexible structures as well as rigid body motion. The fluid flow solution will be performed using our unstructured solution-adaptive flow solver TETHYS. We propose to develop a structural solver based on the Galerkin finite element method and to couple structure and fluid strongly using an immersed boundary method (IBM). We will employ operator overloading to perform automatic code differentiation so that sensitivity and adjoint analysis can be performed on the coupled code. We will couple to parameterized CAD geometry and to the state-of-the-art optimization modules in the DAKOTA toolkit to perform optimization of fluid-structure interaction problems. In Phase I, we will (i) establish the feasibility of the immersed boundary method across the range of Mach numbers, (ii) develop a tightly coupled algorithm for fluid and structure, and (iii) demonstrate that sensitivities and Jacobians may computed seamlessly and accurately for fluid-structure interaction. Though the focus of the proposal is on fluid-structure interaction problems of specific interest to NASA, the methodology will be applicable to a wide range of commercial CFD applications as well.