Turbulence in a large aspect ratio cell

The movie starts with a smooth velocity field which is perturbation from laminar flow and satisfies none of the plane Couette symmetries.
Spatial grid: 96 x 33 x 128; time step: dt = 0.03125.
Movies are solutions of the full Navier-Stokes equations for an incompressible fluid with no-slip boundary condition at the walls.