An analysis of particle trajectories in computer‐simulated turbulent channel flow

The origin of Reynolds stress in turbulent channel flow is analyzed using several ensembles of particle paths computed in a direct numerical simulation. The time interval over which the paths are calculated is shown by several criteria to be sufficiently long so that complete mixing of the particle momenta with the surroundings has occurred. The corresponding mixing length is determined and found to be within the range required by a gradient transport model. However, a small fraction of the particles, which tend to be associated with highly vortical sweep and ejection events, travel well beyond the mixing length and collectively make a major nongradient contribution to Reynolds stress. It is suggested that further analysis of these motions may lead to useful formulas for predicting the nongradient component of momentum transport.

[1]  James M. Wallace,et al.  The wall region in turbulent shear flow , 1972, Journal of Fluid Mechanics.

[2]  J. Lumley,et al.  A First Course in Turbulence , 1972 .

[3]  Numerical Simulation of Lagrangian Turbulent Quantities in Two and Three Dimensions , 1975 .

[4]  R. Brodkey,et al.  On the mechanism of bounded turbulent shear flows , 1978 .

[5]  G. S. Patterson,et al.  DIFFUSION EXPERIMENTS WITH NUMERICALLY INTEGRATED ISOTROPIC TURBULENCE. , 1974 .

[6]  Peter S. Bernard,et al.  A method for computing three-dimensional turbulent flows , 1982 .

[7]  P. Moin,et al.  Turbulence statistics in fully developed channel flow at low Reynolds number , 1987, Journal of Fluid Mechanics.

[8]  David G. Bogard,et al.  Burst detection with single-point velocity measurements , 1986, Journal of Fluid Mechanics.

[9]  S. Orszag,et al.  Prediction of turbulence-induced forces on structures from full numerical solutions of the Navier-Stokes equations , 1987 .

[10]  P. Spalart.  Direct simulation of a turbulent boundary layer up to Rθ = 1410 , 1988, Journal of Fluid Mechanics.

[11]  Robert S. Brodkey,et al.  A stereoscopic visual study of coherent structures in turbulent shear flow , 1978, Journal of Fluid Mechanics.

[12]  S. Corrsin.  Limitations of Gradient Transport Models in Random Walks and in Turbulence , 1975 .

[13]  R. Brodkey,et al.  A visual investigation of the wall region in turbulent flow , 1969, Journal of Fluid Mechanics.

[14]  J. Deardorff,et al.  Lagrangian Statistics from Numerically Integrated Turbulent Shear Flow , 1970 .