  
ZhETF, Vol. 142, 
No. 6,
p. 1284 (December 2012) 
(English translation - JETP, 
	Vol. 115, No. 6,
	p. 1128,
	December 2012
	available online at www.springer.com
)
  
	SCALE-INVARIANT STREAMLINE EQUATIONS AND STRINGS OF SINGULAR VORTICITY FOR PERTURBED ANISOTROPIC SOLUTIONS OF THE NAVIER-STOKES EQUATION
 
	Libin A.
  
	Received: May 23, 2012
  
	 
	 
	A linear combination of a pair of dual anisotropic decaying Beltrami flows with spatially constant amplitudes (the Trkal solutions) with the same eigenvalue of the curl operator and of a constant velocity orthogonal vector to the Beltrami pair yields a triplet solution of the force-free Navier-Stokes equation. The amplitudes slightly variable in space (large scale perturbations) yield the emergence of a time-dependent phase between the dual Beltrami flows and of the upward velocity, which are unstable at large values of the Reynolds number. They also lead to the formation of large-scale curved prisms of streamlines with edges being the strings of singular vorticity.
 
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