Journal of Fluid Mechanics

The density of organized vortices in a turbulent mixing layer

D. W.  Moore a1 and P. G.  Saffman a2
a1 Department of Mathematics, Imperial College, London
a2 Applied Mathematics, California Institute of Technology, Pasadena

Article author query
moore dw   [Google Scholar] 
saffman pg   [Google Scholar] 


It is argued on the basis of exact solutions for uniform vortices in straining fields that vortices of finite cross-section in a row will disintegrate if the spacing is too small. The results are applied to the organized vortex structures observed in turbulent mixing layers. An explanation is provided for the disappearance of these structures as they move downstream and it is deduced that the ratio of average spacing to width should be about 3·5, the width being defined by the maximum slope of the mean velocity. It is shown in an appendix that walls have negligible effect.

(Published Online March 29 2006)
(Received September 16 1974)