Wolf, C. Christian and Schwarz, Clemens and Kaufmann, Kurt and Gardner, Anthony D. and Michaelis, Dirk and Bosbach, Johannes and Schanz, Daniel and Schröder, Andreas (2019) Experimental Study of Secondary Vortex Structures in a Rotor Wake. Experiments in Fluids, 60 (11), pp. 1-16. Springer Nature. doi: 10.1007/s00348-019-2807-1. ISSN 0723-4864.
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Official URL: https://link.springer.com/article/10.1007/s00348-019-2807-1
Abstract
The operation and aerodynamic performance of a helicopter rotor is strongly affected by the structure of its wake, in particular regarding vortex-vortex interactions of hovering rotors. Rotor simulations using modern computational methods have the potential to capture high levels of detail, which recently triggered discussions of secondary vortex braids entangling the primary tip vortices. These structures are highly dependent on the numerical settings and need experimental validation. The current work investigates the wake of a subscale rotor in ground effect by time-resolved and volumetric flow-field measurements using the "Shake-The-Box" technique. Both the Lagrangian tracks of the flow tracers and the derived gradient-based vortex criteria clearly verify the existence of secondary vortices. A post-processing scheme is applied to isolate these vortices in larger data sets. No distinct spatial organization of the structures was observed, but a slightly preferred sense of rotation which agrees to the shear of the wake swirl. The secondary structures were created shortly downstream of the rotor blades, starting at wake ages of approximately 75 degree.
Item URL in elib: | https://elib.dlr.de/128526/ | ||||||||||||||||||||||||||||||||||||
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Document Type: | Article | ||||||||||||||||||||||||||||||||||||
Title: | Experimental Study of Secondary Vortex Structures in a Rotor Wake | ||||||||||||||||||||||||||||||||||||
Authors: |
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Date: | November 2019 | ||||||||||||||||||||||||||||||||||||
Journal or Publication Title: | Experiments in Fluids | ||||||||||||||||||||||||||||||||||||
Refereed publication: | Yes | ||||||||||||||||||||||||||||||||||||
Open Access: | No | ||||||||||||||||||||||||||||||||||||
Gold Open Access: | No | ||||||||||||||||||||||||||||||||||||
In SCOPUS: | Yes | ||||||||||||||||||||||||||||||||||||
In ISI Web of Science: | Yes | ||||||||||||||||||||||||||||||||||||
Volume: | 60 | ||||||||||||||||||||||||||||||||||||
DOI: | 10.1007/s00348-019-2807-1 | ||||||||||||||||||||||||||||||||||||
Page Range: | pp. 1-16 | ||||||||||||||||||||||||||||||||||||
Editors: |
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Publisher: | Springer Nature | ||||||||||||||||||||||||||||||||||||
ISSN: | 0723-4864 | ||||||||||||||||||||||||||||||||||||
Status: | Published | ||||||||||||||||||||||||||||||||||||
Keywords: | Shake the box, volumetric flow measurement, rotor wake | ||||||||||||||||||||||||||||||||||||
HGF - Research field: | Aeronautics, Space and Transport | ||||||||||||||||||||||||||||||||||||
HGF - Program: | Aeronautics | ||||||||||||||||||||||||||||||||||||
HGF - Program Themes: | rotorcraft | ||||||||||||||||||||||||||||||||||||
DLR - Research area: | Aeronautics | ||||||||||||||||||||||||||||||||||||
DLR - Program: | L RR - Rotorcraft Research | ||||||||||||||||||||||||||||||||||||
DLR - Research theme (Project): | L - The Virtual Aerodynamic Rotorcraft (old) | ||||||||||||||||||||||||||||||||||||
Location: | Göttingen | ||||||||||||||||||||||||||||||||||||
Institutes and Institutions: | Institute for Aerodynamics and Flow Technology > Helicopter, GO Institute for Aerodynamics and Flow Technology > Experimental Methods, GO | ||||||||||||||||||||||||||||||||||||
Deposited By: | Winkels, Elisabeth | ||||||||||||||||||||||||||||||||||||
Deposited On: | 07 Nov 2019 11:48 | ||||||||||||||||||||||||||||||||||||
Last Modified: | 12 May 2023 13:05 |
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