- Title
- Spectrum of a passive scalar in moderate Reynolds number homogenous isotropic turbulence
- Creator
- Danaila, L.; Antonia, R. A.
- Relation
- Physics of Fluids Vol. 21, Issue 11
- Publisher Link
- http://dx.doi.org/10.1063/1.3264881
- Publisher
- American Institute of Physics
- Resource Type
- journal article
- Date
- 2009
- Description
- For moderate Reynolds numbers, the spectral scaling exponents of both velocity [E(k)∞k−mu] and the transported passive scalar [Eθ(k)∞k−mθ] fields exhibit departures from the asymptotic prediction mu = mθ = 5/3. However, at the same Reynolds number, the passive scalar spectrum for homogeneous isotropic turbulence is closer to the universal asymptotic state than the dynamic velocity field that transports it. This paper provides a possible explanation for this behavior, in the case of a gaseous mixing with Prandtl (or Schmidt) number Pr ≃ 1. A scenario of the scalar energy transfer toward higher wavenumbers is proposed and validated using experimental data, in which the velocity field itself is actively involved via its characteristic time. A direct relationship between velocity and scalar spectra and therefore between mu and mθ is thus established.
- Subject
- gas mixtures; turbulence; homogenous isotropic turbulence; Reynolds numbers
- Identifier
- uon:6960
- Identifier
- http://hdl.handle.net/1959.13/925264
- Identifier
- ISSN:1070-6631
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