Effect of wake adaptation on rotor hover simulations using unstructured meshes

A three-dimensional inviscid flow solver is developed for simulating the fl owfield of hovering helicopter rotor using unstructured meshes. The flow so lver utilizes a cell-centered finite volume scheme that is based on the Roe 's flux-difference splitting with an implicit Jacobi/Gauss-Seidel time inte gration. Calculations are performed at two operating conditions of subsonic and transonic tip Mach numbers. A solution-adaptive mesh refinement techni que is adopted to improve the resolution of flow features on the blade surf ace. It is demonstrated that the trajectory of the tip vortex can be captur ed through a series of adaptive mesh refinements starting from a very coars e initial grid. It was found that not only the strength of the tip vortex, but also its trajectory, is strongly dependent on the mesh resolution in th e wake. Good agreement is obtained between the numerical result and the exp eriment for both the blade loading and the tip vortex behavior.