LONG-TIME, LARGE-SCALE PROPERTIES OF A RANDOMLY STIRRED COMPRESSIBLE FLUID

The large-scale, long-time properties of a compressible fluid stirred by a Gaussian random force with correlation efifjek-y are investigated. It is shown that when =4+y-d>3 (d=space dimension) the effective sound velocity becomes scale dependent in the limit k0 and the fluid obeys a universal equation of state. The effective Mach number is also scale dependent, reaching a fixed-point value Ma(k)<1 when k0. The predictions of the theory are compared with the results of direct numerical simulations. © 1990 The American Physical Society.