The displacement of the diffraction pattern in the motion of the medium

Diffraction of waves of different physical nature is one of the most important and studied phenomena of nature in connection with its versatile use in devices and measuring techniques. The influence of media motion on the diffraction pattern attracted the attention of researchers in connection with the development of the theory of electrodynamics of moving media and continues to attract attention in connection with a number of unsolved problems of physics. In this paper we consider a model of the diffraction of waves on the slit and lattice, located on a movable substrate (medium). Analytical relations for the calculation of the diffraction pattern intensity distribution are obtained. The significant influence of the medium motion on the diffraction pattern is established. The position of the zero-order maximum does not depend on the motion of the medium, on the one hand, the distance between the diffraction maxima decreases, on the other hand increases, until they disappear. The conditions under which the motion of the medium leads to an asymmetrical appearance of the diffraction intensity distribution, which is not observed in a stationary medium, are established. Generalized conditions of diffraction minima are obtained taking into account the motion of the medium. Shows the effect of the direction of the velocity of motion of the medium on the intensity of the diffraction pattern.