On the recirculating flow of three-dimensional asymmetric bluff bodies



Legeai, Antoine and Cadot, Olivier
(2020) On the recirculating flow of three-dimensional asymmetric bluff bodies. Experiments in Fluids, 61 (12). 249-.

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Abstract

<jats:sec> <jats:title>Abstract</jats:title> <jats:p>The paper investigates the role of geometrical asymmetric modifications of a rectangular flat-backed body on the properties of the recirculating flow at a Reynolds number <jats:inline-formula><jats:alternatives><jats:tex-math>$$Re=1.8\times 10^5$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>R</mml:mi> <mml:mi>e</mml:mi> <mml:mo>=</mml:mo> <mml:mn>1.8</mml:mn> <mml:mo>×</mml:mo> <mml:msup> <mml:mn>10</mml:mn> <mml:mn>5</mml:mn> </mml:msup> </mml:mrow> </mml:math></jats:alternatives></jats:inline-formula>. The reference model has two reflectional symmetries denoted <jats:inline-formula><jats:alternatives><jats:tex-math>$$s_y$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>s</mml:mi> <mml:mi>y</mml:mi> </mml:msub> </mml:math></jats:alternatives></jats:inline-formula> and <jats:inline-formula><jats:alternatives><jats:tex-math>$$s_z$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>s</mml:mi> <mml:mi>z</mml:mi> </mml:msub> </mml:math></jats:alternatives></jats:inline-formula> in both spanwise directions. The flow is subjected to the static instability that leads to two mirrored wake states breaking the symmetry <jats:inline-formula><jats:alternatives><jats:tex-math>$$s_y$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>s</mml:mi> <mml:mi>y</mml:mi> </mml:msub> </mml:math></jats:alternatives></jats:inline-formula>. Two families of geometrical variation of the fore-body and after-body are studied, each breaking one of the reflectional symmetries of the reference model. Geometrical modifications that preserve <jats:inline-formula><jats:alternatives><jats:tex-math>$$s_y$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>s</mml:mi> <mml:mi>y</mml:mi> </mml:msub> </mml:math></jats:alternatives></jats:inline-formula> evidence possibilities of bistable dynamics suppression although the static instability persists. Geometrical modifications that do not preserve <jats:inline-formula><jats:alternatives><jats:tex-math>$$s_y$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>s</mml:mi> <mml:mi>y</mml:mi> </mml:msub> </mml:math></jats:alternatives></jats:inline-formula> produces a large unbalance of both wake states in accordance to recent observations on real cars (Bonnavion et al. in J Wind Eng Ind Aerodyn 184:77–89, 2019). Results offer perspectives for potential drag reduction induced by appropriate coupling of bluff body geometry and wake state selection.</jats:p> </jats:sec> <jats:sec> <jats:title>Graphic abstract</jats:title> </jats:sec>

Item Type: Article
Uncontrolled Keywords: 4012 Fluid Mechanics and Thermal Engineering, 40 Engineering
Depositing User: Symplectic Admin
Date Deposited: 01 Dec 2020 08:31
Last Modified: 21 Jun 2024 09:17
DOI: 10.1007/s00348-020-03083-6
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3108756