Moving grids for nonlinear dynamic aeroelastic simulations

The design process of modern aircraft has become a very complicated task. This is due to increased performance demands and also due to the advent and incorporation of lighter materials. One outcome of this is the increasing importance of the aeroelastic modeling and simulation of a new airplane. This work deals with one very important aspect that is a part of the so-called three-field formulation of the fluid-structure interaction modeling process: the mesh motion of computational fluid grids. A two-dimensional model for a more robust mesh motion scheme based on torsional springs is introduced, then an extension of this model is developed, implemented and tested in a three-dimensional finite-volume-based fluid code. Examples and results are presented that highlight the increased robustness of this new algorithm. Then a technique for the extraction of Rigid-Body mesh motion is developed and tested using an example of a maneuvering airplane. Finally, the need for the realistic simulation of airplane control surfaces lead to the development of a new meshing technique that addresses the problem of the correct incorporation of control surfaces such as rudders, ailerons etc. Starting with a two-dimensional theory and showcasing the basic principles and some test results, a three-dimensional extension is developed and a simple test case has been implemented.