Debernardis, Nicola (2020) BOS-based three-dimensional reconstruction of rotor blade tip vortices. Masterarbeit, Politecnico di Malano.
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Offizielle URL: https://www.politesi.polimi.it/handle/10589/153023
Kurzfassung
A research topic of the Institute of Aerodynamics and Flow Technology in Göttingen is the investigation of blade tip vortices created by helicopter rotors. These vortices are investigated both on free-flying helicopters in different flight situations and on a rotor test stand. A measurement technique that is used to visualize these vortices is the density based background-oriented schlieren (BOS) method. The subject of this work is the three-dimensional vortex reconstruction based on stereoscopic BOS measurements. Therefore, a reconstruction scheme based on epipolar geometry was developed and applied to vortex filaments that were recorded in two different experiments. First, a model helicopter in free flight was investigated and it was possible to reconstruct significant parts of the vortex system up to a maximum vortex age Ψv above 600° during an unsteady takeoff maneuver in ground effect. The developed evaluation scheme was subsequently adapted and applied to the vortex system generated by a rotor test stand with cyclic pitch control. Vortex filaments of the rotor in cyclic pitch conditions were reconstructed and the vortex convection was investigated. The evaluation of a larger sample number of 200 measurement images in quasi-steady conditions showed a significant scatter in the vortex locations, which is in agreement with previous findings. The developed reconstruction scheme allows an automated extraction of vortex positions for a multitude of test conditions at the rotor test stand for future investigations.
elib-URL des Eintrags: | https://elib.dlr.de/135806/ | ||||||||
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Dokumentart: | Hochschulschrift (Masterarbeit) | ||||||||
Titel: | BOS-based three-dimensional reconstruction of rotor blade tip vortices | ||||||||
Autoren: |
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Datum: | 29 April 2020 | ||||||||
Referierte Publikation: | Ja | ||||||||
Open Access: | Nein | ||||||||
Status: | veröffentlicht | ||||||||
Stichwörter: | 3D reconstruction, epipolar geometry, BOS | ||||||||
Institution: | Politecnico di Malano | ||||||||
Abteilung: | Dipartimento di Scienze e Tecnologie Aerospaziali | ||||||||
HGF - Forschungsbereich: | Luftfahrt, Raumfahrt und Verkehr | ||||||||
HGF - Programm: | Luftfahrt | ||||||||
HGF - Programmthema: | Hubschrauber | ||||||||
DLR - Schwerpunkt: | Luftfahrt | ||||||||
DLR - Forschungsgebiet: | L RR - Rotorcraft Research | ||||||||
DLR - Teilgebiet (Projekt, Vorhaben): | L - Der virtuelle Drehflügler (alt) | ||||||||
Standort: | Göttingen | ||||||||
Institute & Einrichtungen: | Institut für Aerodynamik und Strömungstechnik > Hubschrauber, GO | ||||||||
Hinterlegt von: | Carter, Beatrice | ||||||||
Hinterlegt am: | 08 Sep 2020 10:02 | ||||||||
Letzte Änderung: | 14 Jun 2022 12:10 |
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