Dual local and non-local cascades in 3D turbulent Beltrami flows
  We discuss the possibility of dual local and non-local cascades in a 3D turbulent Beltrami flow, with inverse energy cascade and direct helicity cascade, by analogy with 2D turbulence. We discuss the corresponding energy spectrum in both local and non-local case. Comparison with a high Reynolds number turbulent von Karman flow is provided and discussed. 
E. Herbert, F. Daviaud, B. Dubrulle, S. Nazarenko, A. Naso
physics.flu-dyn