Journal ArticleDOI
The reactant concentration spectrum in turbulent mixing with a first-order reaction
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In this paper, the power specturm of a passive scalar contaminant undergoing a first-order chemical reaction and isotropic turbulent mixing is deduced for three different spectral ranges: (i) the inertial-convective range; (ii) the viscous-concave and viscousdiffusive ranges for very large Schmidt number; (iii) the inertial-diffusive range for very small Schmidt number.Abstract:
The power specturm of a passive scalar contaminant undergoing a first-order chemical reaction and isotropic turbulent mixing is deduced for three different spectral ranges: (i) the inertial-convective range; (ii) the viscous-convective and viscous-diffusive ranges for very large Schmidt number; (iii) the inertial-diffusive range for very small Schmidt number. The analysis is restricted to stationary, locally isotropic fields, and to systems so dilute that the heat of reaction has no effect on the reaction rate.read more
Citations
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Journal ArticleDOI
Structure of Turbulent Velocity and Scalar Fields at Large Wavenumbers
TL;DR: For incompressible turbulent flow with large Reynolds and Peclet numbers, mechanisms for the spectral transfer of kinetic energy, heat, and mass at large wavenumbers were proposed in this article.
Journal ArticleDOI
Phytoplankton patchiness: the role of lateral stirring and mixing
TL;DR: The role played by lateral advection and mixing in marine phytoplankton patchy distribution has been discussed in this paper, with a focus on the role of the physical circulation in this regime.
Journal ArticleDOI
An approach to the autoignition of a turbulent mixture
César Dopazo,Edward E. O'Brien +1 more
TL;DR: In this article, the authors considered the turbulent homogeneous mixing of two reactants undergoing a one step, second order, irreversible, exothermic chemical reaction with a rate constant of the Arrhenius type.
Book ChapterDOI
Mixing Mechanisms in Lakes
Dieter M. Imboden,Alfred Wüest +1 more
TL;DR: The thermal motion of atoms and molecules is perceived on the macroscopic level as molecular diffusion as discussed by the authors, as the slow but persistent movement "down along the concentration gradient" although the average speed of the atoms is on the order of tens to hundreds of meters per second, because the molecules do not maintain the same direction long enough.
References
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Journal ArticleDOI
Small-scale variation of convected quantities like temperature in turbulent fluid Part 1. General discussion and the case of small conductivity
TL;DR: In this article, a theoretical investigation of the spectrum of a turbulent fluid at large wave-numbers is presented, taking into account the two effects of convection with the fluid and molecular diffusion with diffusivity k. Hypotheses of the kind made by Kolmogoroff for the small-scale variations of velocity in a turbulent motion at high Reynolds number are assumed to apply also to small-size variations of θ.
Journal ArticleDOI
On the Spectrum of Isotropic Temperature Fluctuations in an Isotropic Turbulence
TL;DR: In this paper, the one-dimensional and three-dimensional spectral equations for a field of isotropic temperature fluctuations in a turbulent environment are derived from the correlation equation. And the relative effective cut-off wave numbers of the two spectra are compared in terms of the fluid Prandtl number.
Journal ArticleDOI
Small-scale variation of convected quantities like temperature in turbulent fluid Part 2. The case of large conductivity
TL;DR: In this paper, the authors extended the analysis reported in Part 1 to the case in which the conductivity κ is large compared with the viscosity ν, the conduction cutoff to the θ-spectrum then being at wave-number (e/κ3)¼.
Journal ArticleDOI
Statistical Behavior of a Reacting Mixture in Isotropic Turbulence
TL;DR: In this paper, the decay rates of mean concentration and fluctuations have been obtained in some limiting cases and with some simplifying assumptions, and the principal hypothesis introduced is that a first-order reaction has no effect on the size structure of the scalar field.