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We investigate the exact results of the Navier-Stokes equations using the methods developed by Polyakov. It is shown that when the velocity field and the density are not independent, the Burgers equation is obtained leading to exact N-point generating functions of velocity field. Our results show that, the operator product expansion has to be generalized both in the absence and the presence of pressure. We find a method to determine the extra terms in the operator product expansion and derive its coefficients and find the first correction to probablity distribuation function. In the general case and for small pressure, we solve the problem perturbatively and find the probablity distribuation function for the Navier-Stokes equation in the mean field approximation.
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