Berechnung der Umströmung von Mehrblattrotoren im schnellen Vorwärtsflug mit einer schwachen Fluid-Struktur-Kopplung

Abstract

A weak coupling procedure for coupling the DLR rotor simulation code S4 and the DLR Euler/Navier-Stokes solver FLOWer is presented. The method allows to produce trimmed CFD solutions for rotors in high speed forward flight with inclusion of elastic blade deformations and viscous effects. The weak coupling procedure is applied to high-speed forward flight test cases of the 7A and the 7AD rotor. Isolated blade computations are carried out for both rotors while the full 4-bladed rotor is simulated only in the 7A case using the chimera approach. The predicted pitching moment computed with the assumption of inviscid flow (Euler solutions) shows large differences compared to the experimental data while viscous (Navier-Stokes) computations are in much better agreement with the measured data. The weak coupling considerably improved the solution compared to the uncoupled CFD computations. The performance difference between the 7A and 7AD rotor in high-speed forward flight was fairly well predicted.