Sound is a natural phenomenon closely related to human life. When the frequency of the sound is too high to exceed the frequency limit of human hearing (according to a large number of investigations, take an integer of 20000 Hz).
People can't perceive the existence of sound, so this high-frequency sound is called "ultra" sound.
● Beam characteristics
Due to the short wavelength of ultrasonic waves, ultrasonic rays can be reflected, refracted, and focused like light rays. Obey the laws of geometric optics. That is, when the ultrasonic ray is reflected from the surface of a material, the incident angle is equal to the reflection angle. When the ray passes through a material and enters another material with a different density, refraction will occur, that is, its transmission direction must be changed. The greater the difference in density of matter, the greater the refraction.
● Absorption properties
When a sound wave propagates in various substances, its intensity will gradually decrease with the increase of the propagation distance, because the substance has to absorb its energy.
For the same substance, the higher the frequency of the sound wave, the stronger the absorption. A sound wave with a certain frequency, the absorption is the worst when propagating in the gas, the absorption is relatively weak when propagating in the liquid, and the absorption is the smallest when propagating in the solid.
● Ultrasonic energy transfer characteristics
Ultrasound is widely used in various industrial sectors, the main point is that it has much stronger power than sound waves. Why is there a strong power? Because when the sound wave reaches a certain material, the molecules in the material also vibrate due to the action of the sound wave. The frequency of the vibration is the same as the frequency of the sound wave. The frequency of the molecular vibration determines the speed of the molecular vibration.
The higher the frequency, the greater the speed. The energy obtained by material molecules due to vibration is not only related to the quality of the molecules, but also determined by the square of the vibration speed of the molecules. Therefore, if the frequency of the sound wave is higher, that is, the material molecules can obtain higher energy. It can be much higher than the sound wave, so it can make the material molecules get a lot of energy; in other words, the ultrasonic wave itself can supply the material with enough power.