Experiments have found that freely relaxing turbulence in inviscid, incompr
essible two-dimensional Euler flows can self-organize into ordered structur
es-vortex crystals-in which a number N-c similar to 2-20 of strong Vortices
form stable; rigidly rotating patterns in a low vorticity background. Ln t
his paper we show that N-c can be roughly predicted from properties of the
flows in the early stage of the turbulent relaxation.