  Gaussian measures of Gibbsian type are associated with some shell models of
3D turbulence; they are constructed by means of the energy, a conserved
quantity for the 3D inviscid and unforced shell model. We prove the existence
of a unique global flow for a stochastic viscous shell model and a global flow
for the deterministic inviscid shell model, with the property that these Gibbs
measures are invariant for these flows.
