## Publication Abstracts

### Canuto et al. 1987

**30**, 3391-3418, doi:10.1063/1.866472.

A model for stationary, fully developed turbulence is presented. The physical model used to describe the nonlinear interations provides an equation for the turbulent spectral energy function F(k) as a function of the time scale for the energy fed into the system, n_{s}^{-1}. The model makes quantitative predictions that are compared with the following available data of a different nature. (a) For turbulent convection, in the case of a constant superadiabatic gradient and for σ << 1 (σ ≡ Prandtl number), the convective flux is computed and compared with the result of the mixing length theory (MLT). For the case of a variable superadiabatic gradient, and for arbitrary σ, as in the case of laboratory convection, the Nusselt number N versus Rayleigh number R relation is found to be N = A_{σ}×R^{(1/3)} as recently determined experimentally. The computed A_{σ} deviates 3% and 8% from recent laboratory data at high R for σ = 6.6 and σ = 2000. (b) The K-ε and Smagorinsky relations. Four alternative expressions for the turbulent (eddy) viscosity are derived (the K-ε and Smagorinsky relations being two of them) and the numerical coefficients apopearing in them are computed. They compare favorably with theoretical estimates (the direct interaction approximation and the renormalization group method), laboratory data, and simulation studies. (c) The spectral function, transfer term, and dissipation term. The spectral energy function F(k), the transfer term T(k), and the dissipation term v×k^{2}×F(k) are computed and compared with laboratory data on grid turbulence. (d) The skewness factor ave(S_{3}) is computed and compared with laboratory data. The turbulence model is extended to treat temperature fluctuations characterized by a spectral function G(k). The main results are (e) when both temperature and velocity fluctuations are taken into account, the rate n_{s}(k), that in the first part was taken to be given by the linear mode analysis, can be determined self-consistently from the model itself; (f) in the inertial-convective range, the model predicts the well-known result G(k) ∼ k^{(-5/3)}; (g) the Kolmogorov and Batchelor constants are shown to be related by Ba = σ_{t}×Ko, where σ_{t} is the turbulent Prandtl number; and (h) in the inertial-conductive range the model predicts G(k) ∼ k^{(-17/3)} for thermally driven convection as well as for advection of a passive scalar, the difference being contained in the numerical coefficient in front. The predicted G(k) vs k compare favorably with experiments for air (σ=0.725), mercury )σ=0.018), and salt water (σ=9.2).

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#### BibTeX Citation

@article{ca02700w, author={Canuto, V. M. and Goldman, I. and Chasnov, J.}, title={A model for fully developed turbulence}, year={1987}, journal={Phys. Fluids}, volume={30}, pages={3391--3418}, doi={10.1063/1.866472}, }

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#### RIS Citation

TY - JOUR ID - ca02700w AU - Canuto, V. M. AU - Goldman, I. AU - Chasnov, J. PY - 1987 TI - A model for fully developed turbulence JA - Phys. Fluids VL - 30 SP - 3391 EP - 3418 DO - 10.1063/1.866472 ER -

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