A Comparison of Overset Methods and Unstructured Remeshing for Modeling Large Rigid Body Motion

A comparison of overset methods and unstructured remeshing was performed using the overset CFD solver Beggar and the unstructured commercial solver FLUENT. The goal of the comparison was to identify the method best suited for modeling the unsteady flows resulting from the large amplitude wing rotations that are characteristic of flapping wing flight. Mesh motion solutions were computed using each solver and compared on the basis of the computational resources required and how well the method preserved the quality of the solution domain. Beggar demonstrated the best performance in terms of resources required for the mesh motion solutions and preserved the quality of the computational domain. Complete flow solutions were computed using Beggar for a full set of Hawkmoth wing kinematics. The flow solutions followed the same computational trends as the mesh motion solutions in terms of computational resources used, and shows promise for preserving solution quality about the wing and in the highly unsteady wake region.