To describe the problem of the random nonlinear waves in fluid, we must know, exactly or approximately, how occurs the process of the vortex separation. For this it is conveniently to use models based on physical considerations and (or) some experimental data. The main attention in this review will be attended to random waves, emerging, for example, at stall flutter. Such waves often appear in fluid, and they are the main cause of many disasters is seas and oceans.
