We show that the ” turbulent ” particle spectra found in numerical simulations of the behavior of matter fields during reheating admit a simple interpretation in terms of hydrodynamic models of the reheating period .
We predict a particle number spectrum n _ { k } \propto k ^ { - \alpha } with \alpha \sim 2 for k \rightarrow 0. Principal PACS No 98.80.Cq ; additional PACS nos : 04.62.+v , 11.10.Wx , 47.27