The  paper of  the  month,  chosen  by  the Editor-in-Chief,  is  "Excitation of waves in a dispersive medium. Example of flow of a bubbly liquid"  by A. Perelomova;

DOI: 10.12693/APhysPolA.146.135

The paper by Perelomova concerns the excitation of waves in a dispersive medium, where the factor causing dispersion is the presence of bubbles. It is a theoretical study of the underlying one-dimensional equations that involve a moving exciter and the resulting dispersive waves. The Author clearly states what aspects of these equations have not been studied in enough detail and presents the solutions in these cases. An interesting discussion of mutual interaction of sound waves and entropy waves is given. It is shown, in particular, that the interaction can reduce the overall density by enlarging the bubbles. This is somewhat similar to isobaric acoustic heating.

I recommend this paper to all physicists interested in fluid mechanics and related phenomena.

The Editor-in-Chief