Nonlinear Krylov acceleration for CFD-based aeroelasticity

A nonlinear computational aeroelasticity model based on the Euler equations of compressible flows and the linear elastodynamic equations for structures is developed. The Euler equations are solved on dynamic meshes using the ALE kinematic description. Thus, the mesh constitutes another field governed by pseudo-elastodynamic equations. The three fields are discretized using proper finite element formulations which satisfy the geometric conservation law. A matcher module is incorporated for the purpose of pairing the grids on the fluid–structure interface and for transferring the loads and displacements between the fluid and structure solvers. Two solution strategies (Gauss–Seidel and Schur-complement) for solving the non-linear aeroelastic system are discussed. By using second-order time discretization scheme, we are able to utilize large time steps in the computations. The numerical results on the AGARD 445.6 aeroelastic wing compare well with the experimental results and show that the Schur-complement coupling algorithm is more robust than the Gauss–Seidel algorithm for relatively large oscillation amplitudes.