Euler Simulation of a Helicopter Configuration in Forward Flight using a Chimera Technique

An existing 3-D Eulercode for the calculation of a rotor in forward flight was extended to be used for helicopter configurations including rotor blades and fuselage. The applied numerical method is a finite-volume approach in a cell-centered formulation based on a Godunov-type algorithm, which solves the 1-D Riemann problem through an upwind scheme in each spatial direction. The time discretisation is performed by using an implicit, iterative relaxation scheme. The unsteady Euler method was validated with numerous test cases, including NASA and ONERA test rotors. A Chimera-technique was used to handle the relative motions of the bodies and the complex geometry. A final test was made with a NASA-fuselage and a two-bladed rotor.