Two-point correlation and integral scale of spatially advancing curved channel flow at friction-velocity-based Reynolds number 550

Matsubara, Koji; Muromoto, Takuya

doi:10.1016/j.ijheatfluidflow.2019.03.003

Cited by 1 publication

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References 36 publications

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“…A strong growth of wall-normal velocity fluctuations and an approximately irrotational mean flow in the centre were observed but they claimed rather surprisingly that the TG vortices contributed to turbulence production on the convex and not the concave side. Matsubara & Miura (2017) and Matsubara & Muromoto (2019) studied a developing flow in a strongly curved channel with planar inflow with up to 550 by DNS. Large-scale structures grow and intensify going downstream according to visualizations, spectra and two-point correlations.…”

Section: Introductionmentioning

confidence: 99%

Turbulent flow in curved channels

Brethouwer

2021

J. Fluid Mech.

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Fully developed turbulent flow in channels with mild to strong longitudinal curvature is studied by direct numerical simulations. The Reynolds based on the bulk mean velocity and channel half-width $\delta$ is fixed at $20\,000$ , resulting in a friction Reynolds number of approximately 1000. Four cases are considered with curvature varying from $\gamma = 2\delta /r_c = 0.033$ to 0.333, where $r_c$ is the curvature radius at the channel centre. Substantial differences between the mean wall shear stress on the convex and concave walls are already observed for $\gamma = 0.033$ . A log-law region is absent and a region with nearly constant mean angular momentum develops in the channel centre for strong curvatures. Spanwise and wall-normal velocity fluctuations are strongly amplified by curvature in the outer region of the concave channel side. Only near the walls, where curvature effects are relatively weak, do the mean velocity and velocity fluctuation profiles approximately collapse when scaled by wall units based on the local friction velocity. Budgets of the streamwise and wall-normal Reynolds-stress equations are presented and turbulence structures are investigated through visualizations and spectra. In the case with strongest curvature, the flow relaminarizes locally near the convex wall. On the concave channel side, large elongated streamwise vortices reminiscent of Taylor–Görtler vortices develop for all curvatures considered. The maximum in the premultiplied two-dimensional wall-normal energy spectrum and co-spectrum shifts towards larger scales with increasing curvature. The large scales substantially contribute to the wall-normal velocity fluctuations and momentum transport on the concave channel side.

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Section: Introductionmentioning

confidence: 99%

Turbulent flow in curved channels

Brethouwer

2021

J. Fluid Mech.

View full text Add to dashboard Cite

show abstract

Two-point correlation and integral scale of spatially advancing curved channel flow at friction-velocity-based Reynolds number 550

Cited by 1 publication

References 36 publications

Turbulent flow in curved channels

Turbulent flow in curved channels

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