On the structure of streamwise wall-shear stress fluctuations in turbulent channel flows

Cheng, Cheng; Li, Weipeng; Lozano-Durán, Adrián; Liu, Hong

doi:10.1017/jfm.2020.639

Cited by 26 publications

(18 citation statements)

References 105 publications

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“…As quantifies , which features the same sign as , this observation is consistent with the work of Cheng et al. (2020), which showed that the footprints of the inactive part of attached eddies populating the logarithmic region are actively connected with large-scale negative . Other values yield similar results and are not shown here for brevity.…”

Section: Resultssupporting

confidence: 91%

Consistency between the attached-eddy model and the inner–outer interaction model: a study of streamwise wall-shear stress fluctuations in a turbulent channel flow

Cheng

2022

J. Fluid Mech.

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The inner–outer interaction model (Marusic et al., Science, vol. 329, 2010, pp. 193–196) and the attached-eddy model (Townsend, Cambridge University Press, 1976) are two fundamental models describing the multiscale turbulence interactions and the organization of energy-containing motions in the logarithmic region of high-Reynolds-number wall-bounded turbulence, respectively. In this paper, by coupling the additive description with the attached-eddy model, the generation process of streamwise wall-shear fluctuations, resulting from wall-attached eddies, is portrayed. Then, by resorting to the inner–outer interaction model, the streamwise wall-shear stress fluctuations generated by attached eddies in a turbulent channel flow are isolated. Direct comparison between the statistics from these two models demonstrates that they are consistent with and complement each other. Meanwhile, we further show that the superpositions of attached eddies follow an additive process strictly by verifying the validity of the strong and extended self-similarity. Moreover, we propose a Gaussian model to characterize the instantaneous distribution of streamwise wall-shear stress, resulting from the attached-eddy superpositions. These findings are important for developing an advanced reduced-order wall model.

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Section: Resultssupporting

confidence: 91%

Consistency between the attached-eddy model and the inner–outer interaction model: a study of streamwise wall-shear stress fluctuations in a turbulent channel flow

Cheng

2022

J. Fluid Mech.

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“…Percolation analysis has been successfully used not only for identifying vortex clusters in turbulent channel flows (del Álamo et al 2006) but also for detecting three-dimensional velocity structures (Sillero 2014;Hwang & Sung 2018) and quadrant events in turbulent channels (Lozano-Durán, Flores & Jiménez 2012) and homogeneous shear turbulence (Dong et al 2017) based on a three-dimensional extension of the classical quadrant analysis (Wallace et al 1972;Willmarth & Lu 1972). More recently, the percolation analysis for threshold selection has also been employed by Cheng et al (2020a) for the identification of scale-based structures of streamwise wall shear stress fluctuations in turbulent channel flows.…”

Section: Identification Methodsmentioning

confidence: 99%

Effects of shear-thinning rheology on near-wall turbulent structures

Arosemena

Andersson

et al. 2021

J. Fluid Mech.

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“…They provided evidence that the large-scale motions near the wall scale in inner units, and Cheng et al. (2020) revealed that the footprints of the large-scale motions manifest as large-scale regions of negative wall friction.…”

Section: Introductionmentioning

confidence: 99%

Ascending–descending and direct–inverse cascades of Reynolds stresses in turbulent Couette flow

et al. 2021

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The interaction between small- and large-scale structures and the coexisting bottom-up and top-down processes are studied in a turbulent plane Couette flow, where space-filling longitudinal rolls appear at relatively low values of the Reynolds number $Re$ . A direct numerical simulation database at $Re_\tau =101$ is built to replicate the highest $Re$ considered in recent experimental work by Kawata & Alfredsson (Phys. Rev. Lett., vol. 120, 2018, 244501). Our study is based on the exact budget equations for the second-order structure function tensor $\left \langle {\delta u_i \delta u_j} \right \rangle$ , i.e. the anisotropic generalized Kolmogorov equations (AGKE). The AGKE study production, redistribution, transport and dissipation of every Reynolds stress tensor component, considering simultaneously the physical space and the space of scales, and properly define the concept of scale in the inhomogeneous wall-normal direction. We show how the large-scale energy-containing motions are involved in the production and redistribution of the turbulent fluctuations. Both bottom-up and top-down interactions occur, and the same is true for direct and inverse cascading. The wall-parallel components $\left \langle {\delta u \delta u} \right \rangle$ and $\left \langle {\delta w \delta w} \right \rangle$ show that both small and large near-wall scales feed the large scales away from the wall. The wall-normal component $\left \langle {\delta v \delta v} \right \rangle$ is different, and shows a dominant top-down dynamics, being produced via pressure-strain redistribution away from the wall and transferred towards near-wall larger scales via an inverse cascade. The off-diagonal component shows a top-down interaction, with both direct and inverse cascades, albeit the latter takes place within a limited range of scales.

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On the structure of streamwise wall-shear stress fluctuations in turbulent channel flows

Abstract: Abstract

Cited by 26 publications

References 105 publications

Consistency between the attached-eddy model and the inner–outer interaction model: a study of streamwise wall-shear stress fluctuations in a turbulent channel flow

Consistency between the attached-eddy model and the inner–outer interaction model: a study of streamwise wall-shear stress fluctuations in a turbulent channel flow

Effects of shear-thinning rheology on near-wall turbulent structures

Ascending–descending and direct–inverse cascades of Reynolds stresses in turbulent Couette flow

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