The Effect of Disordered Perturbations on the Entropy of an Unstable System

The contribution of disordered perturbations in density, velocity, and pressure to the pair entropy of an unstable system, which sets the direction of its evolution, is estimated. The disordered perturbations arising in the incoming flow due to an external influence are calculated by the numerical integration of regular equations of multimoment hydrodynamics supplemented with stochastic components. The distortion of the pair entropy of the system due to disordered perturbations is calculated in a problem of the flow around a stationary solid sphere. It is established that disordered perturbations of the density, velocity, and pressure do not have any noticeable effect on the parameters of the vortex street in the wake behind the sphere.