Solitary-wave solutions of the Navier-Stokes equation

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A method of separation of variables introduced in the classical turbulence theory of fluctuation correlations is applied to inhomogeneous turbulence with density variation and chemical reactions. A system of equations consisting of the one governing mean thermo / gasdynamic quantities, namely, the Reynolds-averaged equations, and the other governing fluctuation correlations, each coupled through turbulent transport terms, are derived. The proposed formalism is applied to the problem of predicting velocity of a flame propagating In a turbulent premixed gas and of predicting Nusselt number of the Benard convection. Regarding the former, the system of equations constitutes an eigenvalue problem with the flame velocity as the eigenvalue, to be determined simultaneously with turbulent transports. Flame velocities calculated for a methaneair premixtare with varied turbulence intensities given at unburnt state are compared with existing experiments also with prediction by the renormalization group theory, and excellent agreement with experiment is observed. The application to the latter, namely high Rayleigh number regime(Ra> 5xlO^5)of Benard convection predicts the mean temperature distribution and the total turbulent heat transfer(the Nusselt number). The agreement is with existing experiment satisfactory considering that the theory does not include any empirical parameters. Power spectrum is also obtained through inverse-Fourier transform.