The spatial origin of-5/3 spectra in grid-generated turbulence
File(s)
Published version
Author(s)
Laizet, S
Nedic, J
Vassilicos, JC
Type
Journal Article
Abstract
A combined wind tunnel and computational study of grid-generated turbulence
along the centreline shows that the close to −5/3 power law signature of energy
spectra in the frequency domain originates relatively close to the grid not only where
the velocity derivative statistics become quite suddenly isotropic but also where
the turbulent fluctuating velocities are very intermittent and non-Gaussian. As the
inlet flow velocity increases, these power laws are increasingly well defined and
increasingly close to −5/3 over an increasing range of frequencies. However, this
range continuously decreases with streamwise distance from the grid even though the
local Reynolds number first increases and then decreases along the same streamwise
extent. The intermittency at the point of origin of the close to −5/3 power spectra
consists of alternations between intense vortex tube clusters with shallow broad-band
spectra and quiescent regions where the velocity fluctuations are smooth with steep
energy spectra.
along the centreline shows that the close to −5/3 power law signature of energy
spectra in the frequency domain originates relatively close to the grid not only where
the velocity derivative statistics become quite suddenly isotropic but also where
the turbulent fluctuating velocities are very intermittent and non-Gaussian. As the
inlet flow velocity increases, these power laws are increasingly well defined and
increasingly close to −5/3 over an increasing range of frequencies. However, this
range continuously decreases with streamwise distance from the grid even though the
local Reynolds number first increases and then decreases along the same streamwise
extent. The intermittency at the point of origin of the close to −5/3 power spectra
consists of alternations between intense vortex tube clusters with shallow broad-band
spectra and quiescent regions where the velocity fluctuations are smooth with steep
energy spectra.
Date Issued
2015-06-29
Date Acceptance
2015-06-10
Citation
Physics of Fluids, 2015, 27 (6)
ISSN
1089-7666
Publisher
American Institute of Physics (AIP)
Journal / Book Title
Physics of Fluids
Volume
27
Issue
6
Copyright Statement
© 2015 AIP Publishing LLC
Subjects
Science & Technology
Technology
Physical Sciences
Mechanics
Physics, Fluids & Plasmas
Physics
SPIRAL VORTEX MODEL
ISOTROPIC TURBULENCE
TAYLOR HYPOTHESIS
FINE-STRUCTURE
FLOWS
DISSIPATION
CYLINDER
SCHEMES
WAKE
Publication Status
Published
Article Number
065115