Fractal grid-induced turbulence strength characterization via piezoelectric thin-film flapping velocimetry

Abstract The centerline streamwise and cross-sectional (x/D h = 0.425) turbulence characteristics of a 2D planar space-filling square-fractal-grid (SFG) composed of self-similar patterns superimposed at multiple length-scales is experimentally unveiled via piezoelectric thin-film flapping velocimet...

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Autores principales:	Ted Sian Lee, Ean Hin Ooi, Wei Sea Chang, Ji Jinn Foo
Formato:	article
Lenguaje:	EN
Publicado:	Nature Portfolio 2021
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/ea2e336257964b9ca614bcb2d1a28fc1
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spelling	oai:doaj.org-article:ea2e336257964b9ca614bcb2d1a28fc12021-12-05T12:14:18ZFractal grid-induced turbulence strength characterization via piezoelectric thin-film flapping velocimetry10.1038/s41598-021-02680-72045-2322https://doaj.org/article/ea2e336257964b9ca614bcb2d1a28fc12021-12-01T00:00:00Zhttps://doi.org/10.1038/s41598-021-02680-7https://doaj.org/toc/2045-2322Abstract The centerline streamwise and cross-sectional (x/D h = 0.425) turbulence characteristics of a 2D planar space-filling square-fractal-grid (SFG) composed of self-similar patterns superimposed at multiple length-scales is experimentally unveiled via piezoelectric thin-film flapping velocimetry (PTFV). The fluid–structure-interaction between a flexible piezoelectric thin-film and SFG-generated turbulent flow at Re Dh = 4.1 × 104 is investigated by analysis of the thin-film’s mechanical response. Measurements of the thin-film-tip deflection δ and induced voltage V demonstrate increasing flow fluctuation strength in the turbulence generation region, followed by rapid decay further downstream of the SFG. Interestingly, SFG-induced turbulence enables the generation of maximum centerline thin-film’s response (V rms , δ rms ) and millinewton turbulence-forcing (turbulence-induced excitation force acting on the thin-film) F rms which are respectively, 7× and 2× larger than the classical square-regular-grid of similar blockage ratio. The low frequency, large-scale energy-containing eddies at SFG’s central opening plays a critical role in driving the thin-film vibration. Most importantly, the SFG-generated turbulence at (y/T = 0.106, z/T = 0.125) away from the centerline allows equivalent mechanical characteristics of turbulence generation and decay, with peak of 1.9× nearer from grid. In short, PTFV provides a unique expression of the SFG-generated turbulence, of which, the equivalent turbulence length-scale and induced-forcing deduced could aid in deciphering the flow dynamics for effective turbulence management.Ted Sian LeeEan Hin OoiWei Sea ChangJi Jinn FooNature PortfolioarticleMedicineRScienceQENScientific Reports, Vol 11, Iss 1, Pp 1-19 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q Ted Sian Lee Ean Hin Ooi Wei Sea Chang Ji Jinn Foo Fractal grid-induced turbulence strength characterization via piezoelectric thin-film flapping velocimetry
description	Abstract The centerline streamwise and cross-sectional (x/D h = 0.425) turbulence characteristics of a 2D planar space-filling square-fractal-grid (SFG) composed of self-similar patterns superimposed at multiple length-scales is experimentally unveiled via piezoelectric thin-film flapping velocimetry (PTFV). The fluid–structure-interaction between a flexible piezoelectric thin-film and SFG-generated turbulent flow at Re Dh = 4.1 × 104 is investigated by analysis of the thin-film’s mechanical response. Measurements of the thin-film-tip deflection δ and induced voltage V demonstrate increasing flow fluctuation strength in the turbulence generation region, followed by rapid decay further downstream of the SFG. Interestingly, SFG-induced turbulence enables the generation of maximum centerline thin-film’s response (V rms , δ rms ) and millinewton turbulence-forcing (turbulence-induced excitation force acting on the thin-film) F rms which are respectively, 7× and 2× larger than the classical square-regular-grid of similar blockage ratio. The low frequency, large-scale energy-containing eddies at SFG’s central opening plays a critical role in driving the thin-film vibration. Most importantly, the SFG-generated turbulence at (y/T = 0.106, z/T = 0.125) away from the centerline allows equivalent mechanical characteristics of turbulence generation and decay, with peak of 1.9× nearer from grid. In short, PTFV provides a unique expression of the SFG-generated turbulence, of which, the equivalent turbulence length-scale and induced-forcing deduced could aid in deciphering the flow dynamics for effective turbulence management.
format	article
author	Ted Sian Lee Ean Hin Ooi Wei Sea Chang Ji Jinn Foo
author_facet	Ted Sian Lee Ean Hin Ooi Wei Sea Chang Ji Jinn Foo
author_sort	Ted Sian Lee
title	Fractal grid-induced turbulence strength characterization via piezoelectric thin-film flapping velocimetry
title_short	Fractal grid-induced turbulence strength characterization via piezoelectric thin-film flapping velocimetry
title_full	Fractal grid-induced turbulence strength characterization via piezoelectric thin-film flapping velocimetry
title_fullStr	Fractal grid-induced turbulence strength characterization via piezoelectric thin-film flapping velocimetry
title_full_unstemmed	Fractal grid-induced turbulence strength characterization via piezoelectric thin-film flapping velocimetry
title_sort	fractal grid-induced turbulence strength characterization via piezoelectric thin-film flapping velocimetry
publisher	Nature Portfolio
publishDate	2021
url	https://doaj.org/article/ea2e336257964b9ca614bcb2d1a28fc1
work_keys_str_mv	AT tedsianlee fractalgridinducedturbulencestrengthcharacterizationviapiezoelectricthinfilmflappingvelocimetry AT eanhinooi fractalgridinducedturbulencestrengthcharacterizationviapiezoelectricthinfilmflappingvelocimetry AT weiseachang fractalgridinducedturbulencestrengthcharacterizationviapiezoelectricthinfilmflappingvelocimetry AT jijinnfoo fractalgridinducedturbulencestrengthcharacterizationviapiezoelectricthinfilmflappingvelocimetry
_version_	1718372168777072640

Fractal grid-induced turbulence strength characterization via piezoelectric thin-film flapping velocimetry

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