Elastic and inelastic collisions of interfacial solitons and integrability of two-layer fluid system subject to horizontal vibrations

We study interfacial waves in a system of two horizontal layers of immiscible inviscid fluids involved into horizontal vibrational motion. We analyze the linear and nonlinear stability properties of the solitons in the system and consider two-soliton collision scenarios. We describe the events of explosive formation of sharp peaks on the interface, which may presumably lead to the layer rapture, and find that beyond the vicinity of this peaks the system dynamics can be represented as a kinetics of a soliton gas.Comment: 6 pages, 6 figures, to appear in Europhys. Let

Capture of particles of dust by convective flow

Interaction of particles of dust with vortex convective flows is under theoretical consideration. It is assumed that the volume fraction of solid phase is small, variations of density due to nonuniform distribution of particles and those caused by temperature nonisothermality of medium are comparable. Equations for the description of thermal buoyancy convection of a dusty medium are developed in the framework of the generalized Boussinesq approximation taking into account finite velocity of particle sedimentation. The capture of a cloud of dust particles by a vortex convective flow is considered, general criterion for the formation of such a cloud is obtained. The peculiarities of a steady state in the form of a dust cloud and backward influence of the solid phase on the carrier flow are studied in detail for a vertical layer heated from the sidewalls. It is shown that in the case, when this backward influence is essential, a hysteresis behavior is possible. The stability analysis of the steady state is performed. It turns out that there is a narrow range of governing parameters, in which such a steady state is stable.Comment: 14 pages, 10 figures, published in Physics of Fluid

Average flow generation by a pulsating flow near a curved interface

This paper is devoted to the study of curvature influence on the average flow generation near the fluid interface. The time averaging of a non-uniform pulsating flow often results in a nonzero average flow in the bulk. The well-known average flow occurs near a solid surface, the so-called Schlichting mechanism of the average flow generation. For flows with a free surface there is the other known mechanism of Longuet-Higgins, according to which the average flow is generated by surface waves traveling on a free surface. We found another mechanism for flow generation near a free surface. This mechanism is associated with the curvature of a free surface and does not depend on its deformations. In the present paper the influence of the curvature is studied for flow generation near the fluid interface. The investigation is carried out on an example of a liquid drop embedded in a viscous liquid. The effective boundary conditions for the tangential stress tensor and tangential velocity jumps are derived. It is shown that for comparable densities of fluids the generation mechanisms are similar to the mechanisms of Dore and Schlichting, which are determined near a flat interface. At a low density (and a low dynamic viscosity) inside the drop all of the above-mentioned mechanisms equally contribute to the average flow generation

Results of application of frequency resonance therapy for treatment of cow mastitis

The physiological aspects of the implementation of the cow milk transfer reflex during machine milking are the result of exposure to the threshold force of a given value of a variable vacuum and simultaneous mechanical irritation by the teat rubber of the udder of the cow udder system. This effect leads to the discovery of sphincters with the subsequent release of the hormone oxytocin by the pituitary gland and the milk accumulation from the alveolar udder tissue. Signal environmental factors (sounds of a vacuum pump, milking machines, feeder) cause reactions in cows not only by irritation but also by frequency. It has been established that exposure to a high-frequency electromagnetic field destroys most of the common causative agents of mastitis-staphylococci, streptococci. For the treatment of mastitis, stimulation of lactation and the reflex of milk flow in cows, it is promising to apply the effect of a high frequency electromagnetic field modulated by radio frequencies, which contribute to the conversion of electromagnetic field energy into energy of nerve impulses and chemical reactions of mitochondrial cellular mechanisms of udder alveolar tissue cells. The use of alternating sets of specific frequencies of a modulating electromagnetic field of high frequency allows the alternation of “killer” frequencies for microbes with stimulating secretion of alveolar cells of the udder and with frequencies that act anti-inflammatory. It is essential to determine the frequencies that create protective inhibition from exposure to extreme irritations of milking factors (increased vacuum, durable worn nipple rubber). With prolonged exposure to an electromagnetic field, such frequencies a repeating conditioned stimulus of a weak strength, which precede and accompany the impact of the milking machine, and stimulate the activity of the nerve centers of the milk yield reflex in cows, creating a dominant lactation