Large eddy interactions in a turbulent channel flow
Abstract
The dynamic processes of large eddies in a turbulent channel flow have been examined by utilizing an orthogonal expansion of the velocity fluctuation, known in the literature as the Proper Orthogonal Decomposition Theorem. The mathematical form of these functions is unknown in contrast to the Fourier analysis. Attention is focused on the nonlinear, turbulenceturbulence interaction process in the dynamical equation for large eddies (the first term in the expansion). The nonlinear interactions of the components of the first mode are treated exactly, but influences of higher modes are modeled. This requires adjustment of both the skewness and the effective Reynolds number so that the energy equilibrium of the large eddies is ensured when the mean velocity distribution is assumed known for experiments. Computational results show that the first mode contributes significantly to turbulent intensities and possesses a structural and statistical character similar to that of the entire flow.
 Publication:

NASA STI/Recon Technical Report N
 Pub Date:
 September 1985
 Bibcode:
 1985STIN...8610464H
 Keywords:

 Channel Flow;
 Decomposition;
 Dynamical Systems;
 Nonlinear Systems;
 Orthogonal Functions;
 Reynolds Stress;
 Turbulence Effects;
 Turbulent Flow;
 Velocity Distribution;
 Vortices;
 Wave Interaction;
 Computational Fluid Dynamics;
 Fourier Analysis;
 Mathematical Models;
 Skewness;
 Fluid Mechanics and Heat Transfer