SIMULATIONS OF 2-DIMENSIONAL TURBULENCE ON THE CONNECTION MACHINE

The two-dimensional Navier-Stokes equations with a large scale instabi lity of the Kuramoto-Sivashinsky type, describing marginally negative eddy-viscosity situations, is simulated on a Connection Machine CM-2. Up to millions of time steps at the resolution 256(2) and tens of thou sands at the resolution 1024(2) are performed. A linear growth phase, a disorganized inverse cascade phase and a structured vortical phase a re successively observed. In the vortical phase monopolar and multipol ar structures are proliferating and display strongly depleted nonlinea rities.