Relationship between the base pressure and the velocity in the near-wake of an Ahmed body

Podvin, Berengere, Pellerin, Stephanie, Fraigneau, Yann, Bonnavion, Guillaume and Cadot, Olivier ORCID: 0000-0001-7323-6418 (2022) Relationship between the base pressure and the velocity in the near-wake of an Ahmed body. PHYSICAL REVIEW FLUIDS, 7 (5). 054602-.

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Official URL: http://dx.doi.org/10.1103/physrevfluids.7.054602

Abstract

We investigate the near-wake flow of an Ahmed body which is characterized by switches between two asymmetric states that are mirrors of each other in the spanwise direction. The work focuses on the relationship between the base pressure distribution and the near-wake velocity field. Using direct numerical simulation obtained at a Reynolds number of 104 based on incoming velocity and body height as well as Bonnavion and Cadot's experiment [G. Bonnavion and O. Cadot, J. Fluid Mech. 854, 196 (2018)JFLSA70022-112010.1017/jfm.2018.630], we perform proper orthogonal decomposition (POD) of the base pressure field. The signature of the switches is given by the amplitude of the most energetic, antisymmetric POD mode. However, switches are also characterized by a global base suction decrease, as well as deformations in both vertical and lateral directions, which all correspond to large-scale symmetric modes. Most of the base suction reduction is due to the two most energetic symmetric modes. Using the linear stochastic estimation technique of Podvin et al. [Exp. Fluids 59, 58 (2018)EXFLDU0723-486410.1007/s00348-018-2513-4], we show that the large scales of the near-wake velocity field can be recovered to some extent from the base pressure modes. Conversely, it is found that the dominant pressure modes and the base suction fluctuation can be well estimated from the POD velocity modes of the near-wake.

Item Type:	Article
Divisions:	Faculty of Science and Engineering > School of Engineering
Depositing User:	Symplectic Admin
Date Deposited:	21 Jun 2022 15:43
Last Modified:	15 Mar 2024 14:05
DOI:	10.1103/PhysRevFluids.7.054602
Related URLs:	Author Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3156919