In the Basilisk software package direct numerical simulation of the dynamics of a liquid cylinder and a cylindrical free edge of a liquid film after imposing modulated noise on the velocity components in the air medium perpendicular to the axis of the cylinder or the edge of the film (rim) is performed. It is shown that the liquid cylinder breaks up into drops as a result of the development of Plateau-Rayleigh instability. For a cylindrical rim at the edge of a flat film, the situation is different: after the noise impact, small disturbances arise on the rim surface, but the undisturbed rim surface after long time compared to the time of cylinder instability development confirms that the noise impact in the case of a cylindrical rim located at the edge of a flat film does not lead to the development of instability. In this regard, it seems incorrect to associate the fragmentation of the rim of a flat film with Plateau-Rayleigh instability.