A STRUCTURED/UNSTRUCTURED EMBEDDED GRID SOLVER FOR HELICOPTER ROTOR FLOWS

This paper summarizes results obtained from a method that solves both the three dimensional thin-layer Navier-Stokes equations and Euler equations for a helicopter rotor flowfield using embedded structured and unstructured grids. The embedded structured grids use an implicit finite-difference method to solve the thin-layer Navier-Stokes equations for the regions close to the rotor blade. The structured grids lie within an unstructured grid that uses an explicit finite-volume method to solve the Euler equations and convect the vorticity downstream onto the following blades. The paper presents a description of the method, the grids systems used and a rotor in hover validation case. Although the current grid system does not adequately resolve the tip vortex core, the computed vortex paths and load predictions demonstrate the methods feasibility.