KOLMOGOROV FLOW IN 3 DIMENSIONS

A numerical study of the long-time evolution of incompressible Navier- Stokes turbulence forced at a single long-wavelength Fourier mode, i.e ., a Kolmogorov flow, has been completed. The boundary conditions are periodic in three dimensions and the forcing is effected by imposing a steady, two-dimensional, sinusoidal shear velocity which is directed along the x-direction and varies along the z-direction. A comparison w ith experimental data shows agreement with measured cross-correlations of the turbulent velocity components which lie in the mean-flow plane . A statistical analysis reveals that the shear-driven turbulence stud ied here has significant spectral anisotropy which increases with wave number. (C) 1997 American Institute of Physics.