Turbulent-laminar patterns

Experiments and numerical simulations have shown that turbulence in
transitional wall-bounded shear flows such as plane Couette and Poiseuille flow
frequently takes the form of long oblique bands, if the domains are sufficiently
large to accommodate them. At their upper Reynolds-number threshold,
laminar regions carve out gaps in otherwise uniform turbulence, thereby forming
regular oblique turbulent-laminar patterns with a large spatial wavelength.
At the lower threshold, isolated turbulent bands sparsely populate otherwise
laminar domains and complete laminarization takes place via their disappearance
characterized by the 2D directed percolation scenario.