On the nature of the organized structures in turbulent near-wall flows

N. B. Nikitin; S. I. Chernyshenko

doi:10.1007/bf02697932

Similarity of undeveloped turbulent near-wall flows

Journal of Engineering Physics ◽

10.1007/bf00859131 ◽

1979 ◽

Vol 37 (6) ◽

pp. 1415-1418

Author(s):

V. A. Gorodtsov

Keyword(s):

Wall Flows ◽

Near Wall

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THE NEAR-WALL STRUCTURES OF TURBULENT WALL FLOWS

Fluid Mechanics and Its Applications - IUTAM Symposium on Elementary Vortices and Coherent Structures: Significance in Turbulence Dynamics ◽

10.1007/1-4020-4181-0_6 ◽

2006 ◽

pp. 53-70 ◽

Cited By ~ 2

Author(s):

Javier Jiménez ◽

Genta Kawahara ◽

Mark P. Simens ◽

Juan C. del Álamo

Keyword(s):

Wall Flows ◽

Wall Structures ◽

Turbulent Wall ◽

Near Wall

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Wall accumulation and spatial localization in particle-laden wall flows

Journal of Fluid Mechanics ◽

10.1017/jfm.2012.65 ◽

2012 ◽

Vol 699 ◽

pp. 50-78 ◽

Cited By ~ 83

Author(s):

G. Sardina ◽

P. Schlatter ◽

L. Brandt ◽

F. Picano ◽

C. M. Casciola

Keyword(s):

Turbulent Flows ◽

Pair Correlation ◽

Turbulent Channel Flow ◽

Wall Turbulence ◽

Small Scale ◽

Wall Region ◽

Inertial Particles ◽

Wall Flows ◽

Domain Truncation ◽

Near Wall

AbstractWe study the two main phenomenologies associated with the transport of inertial particles in turbulent flows, turbophoresis and small-scale clustering. Turbophoresis describes the turbulence-induced wall accumulation of particles dispersed in wall turbulence, while small-scale clustering is a form of local segregation that affects the particle distribution in the presence of fine-scale turbulence. Despite the fact that the two aspects are usually addressed separately, this paper shows that they occur simultaneously in wall-bounded flows, where they represent different aspects of the same process. We study these phenomena by post-processing data from a direct numerical simulation of turbulent channel flow with different populations of inertial particles. It is shown that artificial domain truncation can easily alter the mean particle concentration profile, unless the domain is large enough to exclude possible correlation of the turbulence and the near-wall particle aggregates. The data show a strong link between accumulation level and clustering intensity in the near-wall region. At statistical steady state, most accumulating particles aggregate in strongly directional and almost filamentary structures, as found by considering suitable two-point observables able to extract clustering intensity and anisotropy. The analysis provides quantitative indications of the wall-segregation process as a function of the particle inertia. It is shown that, although the most wall-accumulating particles are too heavy to segregate in homogeneous turbulence, they exhibit the most intense local small-scale clustering near the wall as measured by the singularity exponent of the particle pair correlation function.

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