Nonthermodynamic fluctuations in two-dimensional hydrodynamic systems

The problem of fluctuations in two-dimensional hydrodynamic systems under nonequilibrium conditions due to external forces is studied on the example of a simple model. The effective action is given; this action makes it possible to construct a perturbation series to calculate fluctuation effects in such systems. Renormalizability of this action with an infinite number of vertices is proved; renormalization group equations are derived. A number of solutions of these equations are found; the asymptotic behaviour of the solution is considered in the limit of large logarithms.