Aerodynamics and Aeroacoustics of Distributed Propulsion in Urban Air Mobility
H.N.J. (Hasse) Dekker
Doctoral Candidate
Dr. D. (Daniele) Ragni
Associate Professor
Dr. W.J. (Woutijn) Baars
Assistant Professor
During vertical take-off and landing of multi rotor aerial vehicles, as seen in Urban Air Mobility, the propulsors will be operated in close proximity to the ground. The back pressure caused by the ground results in radial expansion of the individual wakes. Due to this radial expansion, more prononounced aerodynamic rotor-to-rotor interactions can be manifested. These interactions can potentially lead to detrimental effects on the controlability and noise signature of these vehicles during ground operations.
The current research investigates the aerodynamic wake interactions by performing volumetric flow measurements in the flow field around a set of small scaled, counter-rotating, side-by-side rotors. The rotors are positioned over a ground plane. The study makes use of Helium Filled Soap Bubbles to allow a large measurement domain.
One of the found flow phenomena is the formation of an upward moving flow between the rotors, similar to a fountain. The fountain flow is, under certain rotor spacings and heights above the ground plane, being re-ingested into the rotors. This wake re-ingestion changes the inflow conditions to the rotors and can lead to unsteady loading on the blades. The unsteady loading can decrease the rotors efficiency and create additional noise.
Dekker, H. N. J., Ragni, D., Baars, W. J., Scarano, F., & Tuinstra, M. (2022). Aerodynamic Interactions of Side-by-Side Rotors in Ground Proximity. AIAA Journal, Vol. 60, No. 7.
Obtained a BSc (2017) and MSc (2020) in Mechanical Engineering at the University of Twente with a specialisation in Fluid and Thermal engineering. Currently a PhD cadidate at the Delft University of Technology. His work is focused on the aerodynamic and aeroacoustics of distributed propulsion systems.
Daniele Ragni graduated in Thermo-Mechanical Engineering at the Polytechnic University of Marche (2007). Obtained the Ph.D. in 2012 (Faculty of Aerospace Engineering TU Delft) and joined TU Delft at the section of Wind Energy in the AWEP Department in the same year.
Woutijn is an Assistant Professor in the Faculty of Aerospace Engineering at Delft University of Technology. In 2013 he received his Ph.D. degree from the University of Texas at Austin (U.S.A.), in the area of propulsive jet flows and the associated source mechanisms of high-intensity jet noise. After his Ph.D. he became a Research Fellow at the University of Melbourne (Australia), where he made contributions to the physical understanding of high-Reynolds-number wall-bounded flows. Such understanding is vital for manipulation of the viscous drag force acting on transportation systems, e.g. planes and ships. In 2019, he became a Lecturer at RMIT University (Australia) and held an Assistant Professor at Aarhus University (Denmark). Since his start at Delft in 2020, his main research interests include flow control of wall-bounded turbulence
