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Original title:
Aeroelastic instability of differently porous U-profiles in crosswind direction
Authors: Hračov, Stanislav ; Macháček, Michael
Document type: Papers
Conference/Event: International Conference Engineering mechanics 2022, Milovy (CZ), 20220509
Year: 2022
Language: eng
Abstract: Flow-induced vibrations of the flexibly mounted slender U-shaped beams allowed to oscillate in the crosswind direction only are studied experimentally in the wind tunnel. All beams are characterized by a cross section having a side ratio of along-wind to across-wind dimension equal to two. The effects of two depths of U profiles and two porosities of their flanges ( 0 % and 75 %) onto a loss of aeroelastic stability are investigated under the smooth flow conditions and for low Scruton numbers. The results indicate almost similar proneness of the non-porous beams to galloping-type oscillations to a rectangular prism with the same side ratio regardless their depth. The onset of across-wind galloping occurred in these cases at wind velocity very close to von-Kármán-vortex-resonance flow speed, even though the critical velocity predicted by the quasisteady theory is much lower. For porous and shallower U profile this asynchronous quenching also takes\nplace. However, the higher flange porosity reduces significantly not only the vortex-shedding effect, but also causes an increase in the onset galloping velocity above the critical speed determined for non-porous profiles. In the case of deeper U-shaped beam, the effect of higher porosity even suppresses the proneness to galloping
Keywords: aeroelastic instability; asynchronous quenching; galloping; U profile; vortex shedding
Project no.: GA19-21817S (CEP)
Funding provider: GA ČR
Host item entry: Engineering mechanics 2022. Book of full texts, ISBN 978-80-86246-48-2, ISSN 1805-8248
Note: Související webová stránka: https://www.engmech.cz/im/proceedings/show_p/2022/153
Institution: Institute of Theoretical and Applied Mechanics AS ČR (web)
Document availability information: Fulltext is available in the digital repository of the Academy of Sciences.
Original record: http://hdl.handle.net/11104/0331332
Permalink: http://www.nusl.cz/ntk/nusl-508574
The record appears in these collections:
Research > Institutes ASCR > Institute of Theoretical and Applied Mechanics
Conference materials > Papers
Authors: Hračov, Stanislav ; Macháček, Michael
Document type: Papers
Conference/Event: International Conference Engineering mechanics 2022, Milovy (CZ), 20220509
Year: 2022
Language: eng
Abstract: Flow-induced vibrations of the flexibly mounted slender U-shaped beams allowed to oscillate in the crosswind direction only are studied experimentally in the wind tunnel. All beams are characterized by a cross section having a side ratio of along-wind to across-wind dimension equal to two. The effects of two depths of U profiles and two porosities of their flanges ( 0 % and 75 %) onto a loss of aeroelastic stability are investigated under the smooth flow conditions and for low Scruton numbers. The results indicate almost similar proneness of the non-porous beams to galloping-type oscillations to a rectangular prism with the same side ratio regardless their depth. The onset of across-wind galloping occurred in these cases at wind velocity very close to von-Kármán-vortex-resonance flow speed, even though the critical velocity predicted by the quasisteady theory is much lower. For porous and shallower U profile this asynchronous quenching also takes\nplace. However, the higher flange porosity reduces significantly not only the vortex-shedding effect, but also causes an increase in the onset galloping velocity above the critical speed determined for non-porous profiles. In the case of deeper U-shaped beam, the effect of higher porosity even suppresses the proneness to galloping
Keywords: aeroelastic instability; asynchronous quenching; galloping; U profile; vortex shedding
Project no.: GA19-21817S (CEP)
Funding provider: GA ČR
Host item entry: Engineering mechanics 2022. Book of full texts, ISBN 978-80-86246-48-2, ISSN 1805-8248
Note: Související webová stránka: https://www.engmech.cz/im/proceedings/show_p/2022/153
Institution: Institute of Theoretical and Applied Mechanics AS ČR (web)
Document availability information: Fulltext is available in the digital repository of the Academy of Sciences.
Original record: http://hdl.handle.net/11104/0331332
Permalink: http://www.nusl.cz/ntk/nusl-508574
The record appears in these collections:
Research > Institutes ASCR > Institute of Theoretical and Applied Mechanics
Conference materials > Papers
Record created 2022-09-28, last modified 2023-12-06