Decaimento da turbulência convectiva: uma estimativa do coeficiente de difusão turbulento na camada residual

Authors

  • Antônio Goulart Departamento de Ciências Exatas. Universidade Regional Integrada - URI, Santo Ângelo, RS.
  • Gervásio Annes Degrazia Departamento de Física, Centro de Ciências Naturais e Exatas - CCNE Universidade Federal de Santa Maria - UFSM, Santa Maria, RS. https://orcid.org/0000-0002-4304-1748
  • Domenico Anfossi Consiglio Nazionale delle Ricerche - CNR, Istituto di Cosmo-Geofísica -10133, Turin.
  • Haroldo Fraga de Campos Velho Instituto Nacional de Pesquisas Espaciais – INPE.

DOI:

https://doi.org/10.5902/2179460X36901

Abstract

In this work is presented a model that describes the decay of the convective turbulent kinetic energy and that estimates the turbulent diffusion coefficient in the Residual Layer. The dynamic equation for energy spectrum function is obtained from Navier-Stokes equation. The terms that describe the inertial transfer of energy, the production or destruction of energy for thermal effect and the molecular dissipation are considered. The inertial transfer of energy is calculated from the Taylor’s statistical diffusion theory. The Heisenberg’s theory that is based on the concept of a kinematic turbulence viscosity to describe the inertial transfer of energy from the big to the small eddies is used. The term that describes the production or destruction of kinetic energy for thermal effect is obtained from the convective similarity theory considering the Pao’s hypothesis. This hypothesis supposes that energy is extracted of the medium flow in a continuous way, allowing do not explicit a scale of time characteristic. The dynamic equations that describe the turbulent flow are only valid in the three-dimensional space. For this reason it was obtained one spectrum 3-D for convective layer from a model proposed by Kristensen, and of a model for the one-dimensional spectra calculated by Degrazia. The turbulent diffusion coefficient is obtained from the Taylor’s statistical and the similarity convective theories. The results obtained in this work are compared with the LES model

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References

Batchelor, G.K.: 1949, 'The role of big eddies In homogeneous turbulence', Proc. Roy. Soc. A195, 513-532

Batchelor, O.K.: 1959, 'The theory of homogeneous turbulence', monografia de Mecânica e Matemática Aplicada, Cambridge University Press, 197 pp

Degrazia G.A. e Moraes O.L.L.: 1992, 'A model for eddy diffusivity in a stable boundary layer'. Boundary-Layer Meteorol, 58, 205-214

Degrazia G., Anfossi D., Moraes O.L.L. e Trini Castelli S.: 1997, ‘A model for the turbulence parameterization in the residual layer’. AIR POLLUTION V, H. Power, T. Tirabassi e C.A. Brebbia editors, 101-107

Degrazia G.A., Anfossi D., Fraga De Campos Velho H. e Ferrero E.: 1998 ‘A Lagrangian decorrelation time scale for non-homogeneous turbulence’ Boundary-Layer Meteorol., 86, 525-534

Degrazia, G.A. and Anfossi, D.: 1998, ‘Estimation of the Kolmogorov constant Co from classical statistical diffusion theory’, Atmos. Environm., 32, 3611-3614

Hanna S.R: 1981 ‘Lagrangian and Eulerian time-scale i the daytime boundary layer’. J. AppI. Meteor., 20, 242-249

Hinze J.O.: 1975, ‘Turbulence’, Mc Graw Hill, 790 pp

Kaimal J.C. Wyngaard J.C., Izumi Y. e Cote’ O.R.: 1972, ‘Spectral characteristics of surface layer turbulence’ Quart. J.C. Roy. Meteorol. Soc., 98, 563-589

Kim, J. e Mahrt L.: 1992, ‘Simple formulation of turbulent mixing in the stable free atmosphere and nocturnal boundary layer’ Tellus 44A, 381-394

Kristensen, L., Lenschow, D., Kirkegaard, P. e Courtney, M.: 1989, ‘The Spectral Velocity Tensor For Homogeneous Boundary-Layer Turbulence’, Boundary-Layer Meteorol. 47,149-193

Moeng, C. H. e Sullivan P. P.: 1994, ‘A Comparison of Shear- and Buoyancy-Driven Planetary Boundary Layer Flows’, J. Atmos. Sci., 51, 999-1022

Nieuwstadt, F.T.M. e Brost R.A.: 1986, ‘The decay of convective turbulence’, J. Atmos. Sci. 43, 532-546

Pao, Y.H.: 1965, ‘Structure of Turbulent Velocity and Scalar Fields at Large Wavenumbers’, The Physics of Fluids, 8, 1063-1075

Stanisic, M.M.: 1988, ‘The mathematical theory of turbulence’, Berlin Nova York,501pp

Stull, L.B.: 1988, ‘An introduction to Boundary Layer Meteorology’, Kluwer Academic Publishers, Boston, 666 pp.

Published

2000-01-14

How to Cite

Goulart, A., Degrazia, G. A., Anfossi, D., & Velho, H. F. de C. (2000). Decaimento da turbulência convectiva: uma estimativa do coeficiente de difusão turbulento na camada residual. Ciência E Natura, 63–78. https://doi.org/10.5902/2179460X36901

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