Aeroelastic instability of differently porous U-profiles in crosswind direction

0557017 - ÚTAM 2023 RIV CZ eng C - Conference Paper (international conference)
Hračov, Stanislav - Macháček, Michael
Aeroelastic instability of differently porous U-profiles in crosswind direction.
Engineering mechanics 2022. Book of full texts. Prague: Institute of Theoretical and Applied Mechanics of the Czech Academy of Sciences, 2022 - (Fischer, C.; Náprstek, J.), s. 153-156. ISBN 978-80-86246-48-2. ISSN 1805-8248. E-ISSN 1805-8256.
[International Conference Engineering mechanics 2022. Milovy (CZ), 09.05.2022-12.05.2022]
R&D Projects: GA ČR(CZ) GA19-21817S
Institutional support: RVO:68378297
Keywords : aeroelastic instability * galloping * vortex shedding * asynchronous quenching * U profile
OECD category: Civil engineering
https://www.engmech.cz/im/proceedings/show_p/2022/153

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
place. 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
Permanent Link: http://hdl.handle.net/11104/0331332