On helical behavior of turbulence in the ship wake

Turbulent ship wake conservation at a long distance is among unsolved problems at present. It is well known that far wakes have a vortical structure and slowly expand with distance. As was obtained by Dubrovin et al., slow expansion of the wake may be related to the distribution of turbulent viscosity in it. In our work we study the effect of helicity in the wake on the behavior of turbulent viscosity. Taking into account the helical nature of the wake, we can clarify the difference between turbulence inside and outside the wake on the one hand and slowing down of its expansion with time on the other hand.