On vortex entities of 2D turbulence in wavenumber space

To connect vortices in physical space and scales in wavenumber space, spectral definitions for vortex size and momentum are introduced within the framework of a probabilistic method. At a late stage of 2D decaying turbulence, a simple solution is given for the vortex position and momentum probabilities. From the solution, an energy spectrum E(k) for self-similar vortices is constructed, which is in agreement with that observed in numerical simulations. (c) 1995 American Institute of Physics.