COHERENCE IN TURBULENCE: NEW PERSPECTIVE

It is claimed that turbulence in fluids is inherently coherent phenomenon. The coherence shows up clearly as stronglycorrelated helicity uctuations of opposite sign. The helic-ity uctuations have cellular structure forming clusters thatare actually observed as vorticity bands and coherent struc-tures in laboratory turbulence, direct numerical simulationsand most obviously in atmospheric turbulence. The clustersare named BCC - Beltrami Cellular Clusters - because of theobserved nearly total alignment of the velocity and vorticityelds in each particular cell, and hence nearly maximal possi-ble helicity in each cell; although when averaged over all thecells the residual mean helicity in general is small and doesnot play active dynamical role. The Beltrami like uctuationsare short-lived and stabilize only in small and generally contiguous subdomains that are tending to a (multi)fractal in theasymptotic limit of large Reynolds number.

The article of  Eugene Levich COHERENCE IN TURBULENCE: NEW PERSPECTIVE Has been published in Old And New Concepts in Physics Journal in 2009. Открыть: 2009_3_239