Physics of Fluids 7 (1995) pp. 600-605

The decay of axisymmetric homogeneous turbulence

J. R. Chasnov
The Hong Kong University of Science and Technology, Hong Kong

The decay of a homogeneous turbulence generated by an axisymmetric distribution of random impulsive forces acting at the initial instant is studied by means of large-eddy simulations. The impulsive forces may be either parallel or perpendicular to the symmetry axis. For impulsive forces which result in a k4 low wavenumber energy spectrum of the turbulence, it is determined that the flow approaches isotropy on all scales of motion at long-times provided the Reynolds number is large. However, for the type of impulsive forces originally proposed by Saffman [ J. Fluid Mech 27, 581 (1967)], in which a k2 low wavenumber energy spectrum is produced, the turbulence approaches isotropy only at the smallest scales and remains significantly anisotropic at the largest and energy-containing scales. Nevertheless, a similarity state of the flow field establishes itself asymptotically, in which the kinetic energy per unit mass of the turbulence decays as t-6/5.

Full Text: [PDF (762 KB) GZipped PS(692 KB)]

Back to reprints