AMG in TAU: Adjoint Equations and Mesh Deformation

Abstract

Dealing with aerodynamic and aeroelastic tasks typically involves large and ill conditioned linear systems of equations. Usually the solution of these equations is a time critical component of the overall simulation. While common one-level solution techniques tend to be rather inefficient, the appliance of a hierarchical method like algebraic multigrid (AMG) seems to be more promising in order to deal with the increasing demands for the linear solver. However, due to various sources of stiffness within the discretized problem, applying AMG in a straight-forward way is not always possible. In the context of ComFliTe, the usage of classical AMG was evaluated for mesh deformation applications based on linear elasticity. For the solution of flow adjoint equations new and more sophisticated AMG methods were developed. All approaches have been integrated into the state-of-the-art linear solver library SAMG. The following resport describes the modified algorithms utilizing AMG and summarizes the results obtained within the DLR simulation codes throughout the project.