Skin-friction critical points in wall-bounded flows

Cardesa, José I.; Monty, Jason; Soria, Julio; Chong, M. S.

doi:10.1088/1742-6596/506/1/012009

Cited by 23 publications

(51 citation statements)

References 8 publications

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“…x events displayed in figure 9(a,b), exhibit a qualitative behaviour that resembles the results for no-slip critical points (points at the wall where the streamwise and the spanwise skin friction are simultaneously zero) obtained by Cardesa et al (2014) and Chin et al (2018b). The present results, in addition, show that the reverse flow event occurs below the tail of a large-scale low-speed streak.…”

Section: Conditional Velocity Fluctuationssupporting

confidence: 83%

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Extreme wall shear stress events in turbulent pipe flows: spatial characteristics of coherent motions

2020

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Section: Conditional Velocity Fluctuationssupporting

confidence: 83%

“…Although the features observed from conditional backflow wall shear stress fields resemble the results obtained by Chin et al (2018a) and Cardesa et al (2014), figure 5(d), related to a left-sided vortex, unveils a non-symmetric shape of the conditioned τ +…”

Section: Streamwise Wall Shear Stresssupporting

confidence: 58%

Extreme wall shear stress events in turbulent pipe flows: spatial characteristics of coherent motions

2020

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“…Similar observations have been made by Lenaers et al [9] using simulations of turbulent channel flow up to Re τ = 1000 and for turbulent pipe flow by Khoury et al [8]. Cardesa et al [2] also confirm the existence of areas of vanishing wall shear stress in DNS of turbulent channel flow at Re τ = 934 and Re τ = 1834 and associate these so-called critical points with large scale structures that extend up to 800 wall units downstream.…”

Section: Introductionsupporting

confidence: 74%

Experimental evidence of near-wall reverse flow events in a zero pressure gradient turbulent boundary layer

Willert

Cuvier

Foucaut

et al. 2018

Experimental Thermal and Fluid Science

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This study reports on experimentally observed near-wall reverse flow events in a fully developed flat plate boundary layer at zero pressure gradient with Reynolds numbers between Re τ = 1000 and Re τ = 2700. The reverse flow events are captured using high magnification particle image velocimetry sequences with record lengths varying from 50,000 to 126,000 samples. Time resolved particle image sequences allow singular reverse flow events to be followed over several time steps whereas long records of nearly statistically independent samples provide a variety of single snapshots at a higher spatial resolution. The probability of occurrence lies in the range of 0.01% to 0.1% which matches predictions made with direct numerical simulations (DNS). The self-similar size of the reverse flow bubble is about 30-50 wall units in length and 5 wall units in height which also agrees well to DNS data provided by

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“…In prior work, critical points of the WSS vector field and their dynamics have been observed to play an important role in organizing near wall transport (Perry & Chong 1987;Cardesa et al 2014). Also, the structure of WSS lines have been used in developing theories for flow separation using dynamical system methods (Surana et al 2006(Surana et al , 2008.…”

Section: Introductionmentioning

confidence: 99%

Lagrangian wall shear stress structures and near-wall transport in high-Schmidt-number aneurysmal flows

et al. 2016

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The wall shear stress (WSS) vector field provides a signature for near wall convective transport, and can be scaled to obtain a first order approximation of the near wall fluid velocity. The near wall flow field governs mass transfer problems in convection dominated open flows with high Schmidt number, in which case a flux at the wall will lead to a thin concentration boundary layer. Such near wall transport is of particular interest in cardiovascular flows whereby hemodynamics can initiate and progress biological events at the vessel wall. In this study we consider mass transfer processes in pulsatile blood flow of abdominal aortic aneurysms resulting from complex WSS patterns. Specifically, the Lagrangian surface transport of a species released at the vessel wall was advected in forward and backward time based on the near wall velocity field. Exposure time and residence time measures were defined to quantify accumulation of trajectories, as well as the time required to escape the near wall domain. The effect of diffusion and normal velocity was investigated. The trajectories induced by the WSS vector field were observed to form attracting and repelling coherent structures that delineated species distribution inside the boundary layer consistent with exposure and residence time measures. The results indicate that Lagrangian wall shear stress structures can provide a template for near wall transport.

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Skin-friction critical points in wall-bounded flows

Cited by 23 publications

References 8 publications

Extreme wall shear stress events in turbulent pipe flows: spatial characteristics of coherent motions

Extreme wall shear stress events in turbulent pipe flows: spatial characteristics of coherent motions

Experimental evidence of near-wall reverse flow events in a zero pressure gradient turbulent boundary layer

Lagrangian wall shear stress structures and near-wall transport in high-Schmidt-number aneurysmal flows

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