Large-scale and very-large-scale motions in turbulent pipe flow

Large-scale and very-large-scale motions in turbulent pipe flow

2006

In the outer region of fully developed turbulent pipe flow very large-scale motions reach wavelengths more than 8$R$–16$R$ long (where $R$ is the pipe radius), and large-scale motions with wavelengths of $2R$–3R$ occur throughout the layer. The very-large-scale motions are energetic, typically containing half of the turbulent kinetic energy of the streamwise component, and they are unexpectedly active, typically containing more than half of the Reynolds shear stress. The spectra of the $y$-derivatives of the Reynolds shear stress show that the very-large-scale motions contribute about the same amount to the net Reynolds shear force, d$\overline{-u'v'}/{\rm d}y$, as the combination of all smaller motions, including the large-scale motions and the main turbulent motions. The main turbulent motions, defined as the motions small enough to be in a statistical equilibrium (and hence smaller than the large-scale motions) contribute relatively little to the Reynolds shear stress, but they constitute over half of the net Reynolds shear force.

Guala, Michele
Hommema, S. E.
Adrian, R. J.

Graduate Aerospace Laboratories, California Institute of Technology
University of IL, Laboratory for Turbulence and Complex Flow
University of IL, Laboratory for Turbulence and Complex Flow

21

Wastewater

hydraulics
hydraulic
turbulent flow
turbulent flows
statistical analysis

2000-2009

Yes

Do Not Have Copyright Permission

Minnesota Water Research Digital Library