Publication Abstracts

Canuto et al. 1997

Canuto, V.M., M.S. Dubovikov, and A. Dienstfrey, 1997: A dynamical model for turbulence. IV. Buoyancy-driven flows. Phys. Fluids, 9, 2118-2131, doi:10.1063/1.869331.

We apply a recent model of turbulence to turbulent convection at high Rayleigh number Ra and compare the results with new laboratory and DNS data. We derive a closed set of equations for the total turbulent kinetic energy, turbulent kinetic energy in the z direction, temperature variance, and convective flux. The equations are coupled, time dependent, and nonlocal. We solve the equations both analytically and numerically. In the first case, we neglect diffusion and derive the relation Nu = Nu(σ,Ra), where Nu is the Nusselt number and σ is the Prandtl number. For σ ≫ 1, Nu becomes independent of σ for σ ≪ 1, Nu is proportional to σ1/3; for 0.025 (mercury) ≤ σ ≤ 0.7 (helium), Nu is proportional to σ2/7. The numerical solution (with diffusion) yields (a) Nusselt number Nu, ⟨θ2w, ⟨θ2c (temperature variance near the wall and at the center), λT (thermal boundary layer thickness), and Pe (Peclet number) versus Ra, (b) the z profile of mean temperature T, ⟨θ2⟩, horizontal, and vertical Peclet numbers, (c) spectra versus kh (horizontal wave number) ot total kinetic energy, vertical kinetic energy, temperature variance, and temperature flux; (d) dependence of the Nu vs Ra relation of the Prandtl number. For large aspect ratios, the agreement with both laboratory and DNS data is satisfactory. The model contains no free parameters.

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BibTeX Citation

  author={Canuto, V. M. and Dubovikov, M. S. and Dienstfrey, A.},
  title={A dynamical model for turbulence. IV. Buoyancy-driven flows},
  journal={Phys. Fluids},

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RIS Citation

ID  - ca07100z
AU  - Canuto, V. M.
AU  - Dubovikov, M. S.
AU  - Dienstfrey, A.
PY  - 1997
TI  - A dynamical model for turbulence. IV. Buoyancy-driven flows
JA  - Phys. Fluids
VL  - 9
SP  - 2118
EP  - 2131
DO  - 10.1063/1.869331
ER  -

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