SPECTRA OF LOCAL AND NONLOCAL 2-DIMENSIONAL TURBULENCE

We propose a family of two-dimensional incompressible fluid models ind exed by a parameter alpha epsilon[0, infinity], and discuss the spectr al scaling properties for homogeneous, isotropic turbulence in these m odels. The family includes two physically realizable members. It is sh own that the enstrophy cascade is spectrally local for alpha < 2, but becomes dominated by nonlocal interactions for alpha > 2. Numerical si mulations indicate that the spectral slopes are systematically steeper than those predicted by the local scaling argument.