Results 181 to 190 of about 60,257 (227)

On the decay of isotropic turbulence

Journal of Fluid Mechanics, 2006
We investigate the decay of freely evolving isotropic turbulence. There are two canonical cases: $E(k \,{\to}\, 0)\,{\sim}\, Lk^2$ and $E(k \,{\to}\, 0)\,{\sim}\, Ik^4,$$L$ and $I$ being the Saffman and Loitsyansky integrals respectively. We focus on the second of these. Numerical simulations are performed in a periodic domain whose dimensions, $l_{box}
P. A. Davidson, Y. Kaneda, T. Ishida
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Noise from Isotropic Turbulence

AIAA Journal, 2017
Turbulence naturally returns to isotropy and often possesses locally isotropic regions. This paper presents a new method to predict noise from turbulence that has returned or is returning to isotro...
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Particle Clustering in Isotropic Turbulent Flow

Fluid Dynamics, 2003
zbMATH Open Web Interface contents unavailable due to conflicting licenses.
Alipchenkov, V. M., Zajchik, L. I.
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Spectrum of Isotropic Turbulence

The Physics of Fluids, 1967
Two expressions are obtained for the turbulent viscosity associated with the transfer of mean-square vorticity across the spectrum. Both involve the three-dimensional energy-spectrum function E and on equating them, a differential equation for the spectrum is obtained. For small wavenumber magnitudes and at high Reynolds number, E = (27/3/3) ε2/3 k−5/3,
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Isotropic Turbulence and Spectra

2011
The knowledge gained from similarity theory is applied in many fields of natural and engineering science, among others, in fluid mechanics. In this field, similarity considerations are often used for providing insight into the flow phenomenon and for generalization of results.
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Approximations for Steady-State Isotropic Turbulence

The Physics of Fluids, 1964
The direct-interaction approximation for turbulence maintained by stationary, isotropic, random stirring forces is formulated in the wavenumber-frequency domain. Further, simplifying approximations are made. The final equations involve the wavenumber energy-spectrum, a characteristic correlation frequency for each wavenumber, and a characteristic ...
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On the Theory of Isotropic Turbulence

Applied Mechanics Reviews, 1989
The theory of isotropic turbulence is investigated. In particular it is established that, for self-similar turbulence, energy transfer occurs in two distinct invariant modes. Implications of this result are discussed. The related decay of turbulence intensity is determined.
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Temperature structure functions in isotropic turbulence

Physical Review A, 1991
A method of modeling isotropic turbulence with a passive scalar is presented that can derive the high-order temperature structure functions with reasonable asymptotic behavior. As a necessary tool for this purpose, a theory of joint intermittency exponents of the dissipation of turbulent energy and scalar variance is developed, which is led to be ...
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Acoustic Radiation from Isotropic Turbulence

The Journal of the Acoustical Society of America, 1958
For low Mach number turbulence, Lighthill has given a result which expresses the acoustic radiation of turbulent fluid in terms of a fourth-rank velocity correlation. Through the use of the Navier-Stokes equation this relation can be put in terms of the space-time pressure correlation. For very large Reynolds number turbulence (in the inertial subrange
W. C. Meecham, G. W. Ford
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Isotropic Turbulence and Inertial-Range Structure

The Physics of Fluids, 1966
The abridged Lagrangian-History Direct Interaction closure approximation is interpreted physically and used to analyze energy transfer, effective eddy viscosities, and Lagrangian spacetime statistics in stationary and decaying isotropic turbulence. The results are then specialized to the inertial range. Numerical values are predicted for the Kolmogorov
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