Michaelis, Dirk and Schwarz, Clemens and Bosbach, Johannes and Dierksheide, Uwe and Lemke, Christian and Wolf, C. Christian and Schanz, Daniel and Schröder, Andreas (2018) Time-resolved Large-scale Volumetric Flow Measurement of a Helicopter Model Using Helium-filled Soap Bubbles. In: 71st Annual Meeting of the APS Division of Fluid Dynamics. 71st Annual Meeting of the APS Division of Fluid Dynamics 2018, 2018-11-18 - 2018-11-20, Atlanta, Georgia, USA.
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Official URL: http://meetings.aps.org/Meeting/DFD18/Session/D14.8
Abstract
This study describes time-resolved large-scale volumetric flow measurement of a helicopter model (1.55 m rotor-span, cord length = 61 mm) in close-to-ground condition (height = 0.5 D) at Reynolds number 4.1 x 10^5 (rotational frequency = 20.83 Hz) to examine CFD predicted secondary vortex structures (originating from primary rotor-tip vortices), as well as ground effects. Five high-repetition-rate cameras are used to image tracer particles (Helium-filled soap bubbles HFSB) in a 400 x 600 x 400 mm³ measurement volume at 1.7 kHz recording rate. HFSB tracer particles are illuminated by an array of over-pulsed high-power LED's. 50 sequences, with 3800 images each, at different angles of attack and different particle densities are recorded. The images are analysed using Shake-the-Box (time resolved particle tracking) to gather dense Lagrangian particle tracks. Further, data assimilation techniques (Flow Fit, Vortex-In-Cell VIC#) are applied for high-resolution grid-reconstruction of velocity, vorticity, acceleration and pressure (pressure from PTV) from the track data. First analysis confirms the presence of secondary vortex structures and reveals spanwise oriented vortex tubes close to the ground. Low pressure and high acceleration (150 g) are measured in the primary tip vortices.
Item URL in elib: | https://elib.dlr.de/126221/ | ||||||||||||||||||||||||||||||||||||
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Document Type: | Conference or Workshop Item (Speech) | ||||||||||||||||||||||||||||||||||||
Title: | Time-resolved Large-scale Volumetric Flow Measurement of a Helicopter Model Using Helium-filled Soap Bubbles | ||||||||||||||||||||||||||||||||||||
Authors: |
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Date: | November 2018 | ||||||||||||||||||||||||||||||||||||
Journal or Publication Title: | 71st Annual Meeting of the APS Division of Fluid Dynamics | ||||||||||||||||||||||||||||||||||||
Refereed publication: | Yes | ||||||||||||||||||||||||||||||||||||
Open Access: | No | ||||||||||||||||||||||||||||||||||||
Gold Open Access: | No | ||||||||||||||||||||||||||||||||||||
In SCOPUS: | No | ||||||||||||||||||||||||||||||||||||
In ISI Web of Science: | No | ||||||||||||||||||||||||||||||||||||
Status: | Published | ||||||||||||||||||||||||||||||||||||
Keywords: | rotor wake, volumetric flow measurements, blade tip vortices, shake-the-box, soap bubbles | ||||||||||||||||||||||||||||||||||||
Event Title: | 71st Annual Meeting of the APS Division of Fluid Dynamics 2018 | ||||||||||||||||||||||||||||||||||||
Event Location: | Atlanta, Georgia, USA | ||||||||||||||||||||||||||||||||||||
Event Type: | international Conference | ||||||||||||||||||||||||||||||||||||
Event Start Date: | 18 November 2018 | ||||||||||||||||||||||||||||||||||||
Event End Date: | 20 November 2018 | ||||||||||||||||||||||||||||||||||||
Organizer: | American Physical Society APS | ||||||||||||||||||||||||||||||||||||
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: | 12 Feb 2019 03:33 | ||||||||||||||||||||||||||||||||||||
Last Modified: | 24 Apr 2024 20:30 |
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