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ISSN Online: 2379-1748

ISBN Flash Drive: 978-1-56700-483-0

ISBN Online: 978-1-56700-482-3

4th Thermal and Fluids Engineering Conference
April, 14–17, 2019 , Las Vegas, NV, USA

SYMMETRIC AND ANTISYMMETIC CHARACTERIZATION OF TURBULENT FLOW PAST A SQUARE CYLINDER OF LOW ASPECT RATIO

Get access (open in a dialog) pages 767-775
DOI: 10.1615/TFEC2019.fli.028033

摘要

In this paper, the turbulent wake velocity fields past a square cylinder of a small height-to-width aspect ratio and submerged in a turbulent boundary layer are measured with time-resolved particle image velocimetry (TR-PIV). Proper orthogonal decomposition (POD) is applied to characterize the spatial-temporal TR-PIV data of flow fields and extract the large-scale coherent motions in the cylinder wake. To reduce the effect of data error propagation and reinforce the existing symmetry property of the cylinder wake, a 'pre-filter' strategy of symmetrization is adopted. The low-order energetic modes are then used to reconstruct and represent the dominant fluctuating characteristics of near-wake flow. The antisymmetric and symmetric POD modes successfully reveal the occurrence and mechanism of two different types of vortex shedding process from the cylinder, namely the Karman- and arch- type vortices.