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A turbulence dissipation inhomogeneity scaling in the wake of two side-by-side square prisms
Published online by Cambridge University Press: 04 August 2021
Abstract
We experimentally study how the turbulent energy dissipation rate scales in the cross-stream direction of turbulent wake flows generated by two side-by-side square prisms. We consider three different such turbulent flows with gap ratios $G/H=1.25$,
$2.4$ and
$3.5$, where
$G$ is the distance between the prisms and
$H$ is the prism width. These three flows have a very different dynamics, inhomogeneities and large-scale features. The measurements were taken with a multi-camera particle image velocimetry system at several streamwise locations between
$2.5H$ and
$20H$ downstream of the prisms. After removing the large-scale most energetic coherent structures, the normalised turbulence dissipation coefficient
$C'_{\epsilon }$ of the remaining incoherent turbulence is found to scale as
$C'_{\epsilon } \sim (\sqrt {Re_{L}}/Re'_{\lambda })^{3/2}$ along the highly inhomogeneous cross-stream direction for all streamwise locations tested in all three flows and for all three inlet Reynolds numbers considered;
$Re'_{\lambda }$ and
$Re_{L}$ are, respectively, a Taylor length-based and an integral length-based Reynolds number of the remaining incoherent turbulence.
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- © The Author(s), 2021. Published by Cambridge University Press
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