Reflection Of Harmonic Waves Research Articles

The effect of diffusion on the acoustic properties of a bubble fluid

The problems of wave propagation in bubble media have been of great interest to researchers for almost half a century in connection with the wide distribution of these systems in nature and their intensive use in modern technologies. It is known from the literature that the intensity of attenuation of sound disturbances in the gas-liquid media under consideration is mainly determined by the thermophysical characteristics of the gas in the bubbles. It turns out that these effects are significantly enhanced with increasing vapor concentration due to an increase in the temperature of the system. There are a large number of publications in the literature in which various statements of the wave action on bubble media have been considered. In the present work, the propagation of small perturbations in a liquid with bubbles filled with vapor and a gas insoluble in the liquid phase is considered in the plane one-dimensional and single-velocity approximations. The rate of liquid evaporation (condensation) inside the bubble was determined from the condition of heat balance. To take into account interphase heat and mass transfer, the heat conduction and diffusion equations inside the bubble and the heat conduction equation in the fluid around the bubble are used. From the condition for the existence of a solution in the form of a decaying traveling wave, taking into account the effects of acoustic unloading of bubbles, the dispersion equation is written. From the condition for the existence of a solution in the form of a decaying traveling wave, taking into account the effects of acoustic unloading of bubbles, the dispersion equation is written. Based on the obtained dispersion equation, relations are written for the equilibrium speed of sound depending on the thermophysical parameters of the medium and numerical calculations are performed for water with vapor-gas bubbles. The features of the reflection of harmonic waves from the interface between the “pure” liquid and liquid with vapor-gas bubbles are studied. The influence of the perturbation frequency and the temperature of the medium on the attenuation coefficient of the acoustic wave is studied. The influence of diffusion on the evolution of harmonic waves is analyzed.

Effect of thermoelastic scattering in a liquid and solid body on the reflection of harmonic waves from a plane boundary of separation

Effect of thermoelastic scattering in a liquid and solid body on the reflection of harmonic waves from a plane boundary of separation

On the reflection of harmonic waves in fiber-reinforced materials

This paper is concerned with the reflection of plane waves at a plane boundary in materials reinforced by inextensible and almost inextensible fibers. In such materials, there exist three distinct types of plane harmonic waves. In general, if any of these waves impinges'on a plane boundary, it will reflect into all three types of waves. The amount of energy that is carried by each reflected wave depends on the direction of propagation and on the fiber direction. This dependence is exhibited in the paper. The solutions for almost-inextensible fibers are obtained by expansion from the expressions for inextensible fibers. A comparison is made between the two sets of results and the various similarities and differences are pointed out.