Frequently asked questions
- question: In what environment can propagate ultrasonic vibrations?
- answer: ultrasonic oscillations can only propagate in elastic media. Transmission of vibrations in such an environment cause the elastic connection between the individual particles.
- question: how a wave propagates in elastic media?
- answer in an elastic medium subject to longitudinal acoustic waves. in the longitudinal wave the particles oscillate through the medium of propagation.
- question: what is the ultrasonic wave?
- answer the ultrasonic wave is a process of sequential transfer of the vibrational state from one particle of an elastic medium to another particle.
- question: what is the wave field?
- answer: the wave field is the space in which ultrasonic waves propagate
- question as ultrasonic vibrations affect the elastic medium?
- answer: the propagation of ultrasonic wave changes the distances between the particles and therefore the density and pressure.
Basic relations that characterize the elastic medium.
A. Extending
By extension we mean relative change of the elastic medium.
Two. Thickening
The volume change is accompanied by a change in density of the medium.
Three. The relationship between the expansion and refinementWhen all the changes of the mass medium it remains constant.
For small deformations of concentration is numerically equal to the expansion and opposite in sign.
Physically, it is clear that if there was an increase in volume, the density of the medium it must decrease and vice versa.
The pressure in the environment is a unique function of density.
The total pressure in the environment, covered by the wave motion can be considered as consisting of two parts, namely, the initial hydrostatic pressure and dynamic, or excessive, the pressure caused by the action of ultrasonic waves.
Under the influence of ultrasonic waves in a medium density changes occur that lead to excessive pressure.
Excessive pressure in the environment can be defined as a quantitative increase in pressure caused by changes in density. - question: what is the connection between waves and waves of displacement pressure
- answer: Distribution of the wave displacement is accompanied by changes in the distances between the particles of the medium.
Particle displacement associated with the corresponding deformation volume, leading in turn to pressure changes in the environment. Therefore, simultaneously with the displacement wave propagates in the medium pressure wave.
The waves of displacement and the pressure wave is characterized by various parties of the same wave process.
Under the influence of wave particle displacement protection begin to oscillate along the propagation.Under the influence of waves on the areas ab and de particles of the medium closer together, and parted in the area bd. In places
approach of the particles formed of compression (in the areas ab and de). At the same plots bd, where the particles are moved away from each other, there was dilution zone.
The density of the medium in the local approach of the particles increased and decreased in the zone of rarefaction.
At points A and E, where the displacement of particles in a given time is zero, the convergence of the particles, and hence the acoustic pressure reaches its maximum value. The minimum pressure occurs at the point where the greatest discrepancy between the particles.As the wave propagation medium particles lying on the x-axis away from the origin, one by one will be involved in the wave motion, repeating the oscillations of the particles, began to waver under the influence of the wave before.
Therefore, the compression and rarefaction will move with the wave at a rate equal to the velocity of wave propagation.
Wave of displacement, thus, is accompanied by a wave of pressure. As can be seen, the two waves are different aspects of the wave process. - question whether there are thermal processes in the environment under the influence of ultrasonic waves.
- answer: When it is compressed medium heat, and when negative pressure - cooling. This circumstance is associated with changes in the propagation velocity of longitudinal sound waves in an elastic medium.
- question is not whether the ultrasonic vibrations to destroy the cement stone in the casing?
- answer is no. cement stone is an elastic medium and is subject to all laws of wave propagation in elastic media. ultrasonic vibrations do not have the power to destroy the bonds between the particles of cement.
