1. Chair of Aerodynamics and Fluid Mechanics, Technical Univ. of Munich, Boltzmannstr, 15, Garching 85748, Germany (corresponding author). ORCID: .
2. Kopter Germany GmbH, Altlaufstr, 34, Höhenkirchen-Siegertsbrunn 85635, Germany.
3. Professor, Chair of Aerodynamics and Fluid Mechanics, Technical Univ. of Munich, Boltzmannstr, 15, Garching 85748, Germany.