Kissing, Johannes ; Kriegseis, Jochen ; Li, Zhenyao ; Feng, Lihao ; Hussong, Jeanette ; Tropea, Cameron (2024)
Insights into leading edge vortex formation and detachment on a pitching and plunging flat plate.
In: Experiments in Fluids : Experimental Methods and their Applications to Fluid Flow, 2020, 61 (9)
doi: 10.26083/tuprints-00023907
Artikel, Zweitveröffentlichung, Verlagsversion
 | Es ist eine neuere Version dieses Eintrags verfügbar. |
Kurzbeschreibung (Abstract)
The present study is a prelude to applying different flow control devices on pitching and plunging airfoils with the intention of controlling the growth of the leading edge vortex (LEV); hence, the lift under unsteady stall conditions. As a pre-requisite the parameters influencing the development of the LEV topology must be fully understood and this constitutes the main motivation of the present experimental investigation. The aims of this study are twofold. First, an approach is introduced to validate the comparability between flow fields and LEV characteristics of two different facilities using water and air as working media by making use of a common baseline case. The motivation behind this comparison is that with two facilities the overall parameter range can be significantly expanded. This comparison includes an overview of the respective parameter ranges, control of the airfoil kinematics and careful scrutiny of how post-processing procedures of velocity data from time-resolved particle image velocimetry (PIV) influence the integral properties and topological features used to characterise the LEV development. Second, and based on results coming from both facilities, the appearance of secondary structures and their effect on LEV detachment over an extended parameter range is studied. A Lagrangian flow field analysis based on finite-time Lyapunov Exponent (FTLE) ridges allows precise identification of secondary structures and reveals that their emergence is closely correlated to a vortex Reynolds number threshold computed from the LEV circulation. This threshold is used to model the temporal onset of secondary structures. Further analysis indicates that the emergence of secondary structures causes the LEV to stop accumulating circulation if the shear layer angle at the leading edge of the flat plate has ceased to increase. This information is of particular importance for advanced flow control applications, since efforts to strengthen and/or prolong LEV growth rely on precise knowledge about where and when to apply flow control measures.
| Typ des Eintrags: | Artikel |
|---|---|
| Erschienen: | 2024 |
| Autor(en): | Kissing, Johannes ; Kriegseis, Jochen ; Li, Zhenyao ; Feng, Lihao ; Hussong, Jeanette ; Tropea, Cameron |
| Art des Eintrags: | Zweitveröffentlichung |
| Titel: | Insights into leading edge vortex formation and detachment on a pitching and plunging flat plate |
| Sprache: | Englisch |
| Publikationsjahr: | 30 April 2024 |
| Ort: | Darmstadt |
| Publikationsdatum der Erstveröffentlichung: | September 2020 |
| Ort der Erstveröffentlichung: | Berlin ; Heidelberg |
| Verlag: | Springer |
| Titel der Zeitschrift, Zeitung oder Schriftenreihe: | Experiments in Fluids : Experimental Methods and their Applications to Fluid Flow |
| Jahrgang/Volume einer Zeitschrift: | 61 |
| (Heft-)Nummer: | 9 |
| Kollation: | 18 Seiten |
| DOI: | 10.26083/tuprints-00023907 |
| URL / URN: | https://tuprints.ulb.tu-darmstadt.de/23907 |
| Zugehörige Links: | |
| Herkunft: | Zweitveröffentlichung DeepGreen |
| Kurzbeschreibung (Abstract): | The present study is a prelude to applying different flow control devices on pitching and plunging airfoils with the intention of controlling the growth of the leading edge vortex (LEV); hence, the lift under unsteady stall conditions. As a pre-requisite the parameters influencing the development of the LEV topology must be fully understood and this constitutes the main motivation of the present experimental investigation. The aims of this study are twofold. First, an approach is introduced to validate the comparability between flow fields and LEV characteristics of two different facilities using water and air as working media by making use of a common baseline case. The motivation behind this comparison is that with two facilities the overall parameter range can be significantly expanded. This comparison includes an overview of the respective parameter ranges, control of the airfoil kinematics and careful scrutiny of how post-processing procedures of velocity data from time-resolved particle image velocimetry (PIV) influence the integral properties and topological features used to characterise the LEV development. Second, and based on results coming from both facilities, the appearance of secondary structures and their effect on LEV detachment over an extended parameter range is studied. A Lagrangian flow field analysis based on finite-time Lyapunov Exponent (FTLE) ridges allows precise identification of secondary structures and reveals that their emergence is closely correlated to a vortex Reynolds number threshold computed from the LEV circulation. This threshold is used to model the temporal onset of secondary structures. Further analysis indicates that the emergence of secondary structures causes the LEV to stop accumulating circulation if the shear layer angle at the leading edge of the flat plate has ceased to increase. This information is of particular importance for advanced flow control applications, since efforts to strengthen and/or prolong LEV growth rely on precise knowledge about where and when to apply flow control measures. |
| Freie Schlagworte: | Engineering Fluid Dynamics, Fluid- and Aerodynamics, Engineering Thermodynamics, Heat and Mass Transfer |
| ID-Nummer: | Artikel-ID: 208 |
| Status: | Verlagsversion |
| URN: | urn:nbn:de:tuda-tuprints-239079 |
| Sachgruppe der Dewey Dezimalklassifikatin (DDC): | 500 Naturwissenschaften und Mathematik > 530 Physik 600 Technik, Medizin, angewandte Wissenschaften > 620 Ingenieurwissenschaften und Maschinenbau |
| Fachbereich(e)/-gebiet(e): | 16 Fachbereich Maschinenbau 16 Fachbereich Maschinenbau > Fachgebiet Strömungslehre und Aerodynamik (SLA) |
| Hinterlegungsdatum: | 30 Apr 2024 11:21 |
| Letzte Änderung: | 02 Mai 2024 07:38 |
| PPN: | |
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| Suche nach Titel in: | TUfind oder in Google |
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- Insights into leading edge vortex formation and detachment on a pitching and plunging flat plate. (deposited 30 Apr 2024 11:21) [Gegenwärtig angezeigt]
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