Acoustic and aerodynamic evaluation of DLR small-scale rotor configuration within GARTEUR AG 26

This paper presents the activities performed in the GARTEUR Action Group HC/AG-26 to study the acoustic and aerodynamic characteristics of small rotor configurations, including the influence of the rotor-rotor interactions. This paper will focus on comparisons between numerical activities and wind tunnel results on a small rotor provided by DLR. The wind tunnel modelss included a Rotor/Rotor/Pylon in isolated, tandem and coaxial configuration. The wind tunnel experiments for acoustics were performed in DLR's Acoustic Wind Tunnel Braunschweig (AWB) and PIV test were performed in CIRA within a common CIRA/DLR test program. For simulations, the numerical approaches from each partner are applied. The aerodynamic simulations necessary for the aeroacoustic predictions are conducted with a range of fidelity numerical methods, varying from lifting line to CFD. The acoustic and aerodynamic predictions are compared to test data, including performance, PIV and acoustic directivity.