The wavelength of ultrasonic wave is relatively shorter than that of sound wave, and the usual obstacles are much larger than ultrasonic wave. So the diffraction ability of ultrasonic wave is not very strong. Under the condition of constant medium density, ultrasonic waves can travel in a straight line along the direction of waves. The shorter the wavelength of ultrasonic wave, the better the direct transmission ability.
When sound propagates in the air, it pushes the particles in the air to vibrate back and forth and do work on them. Sound wave power is a physical quantity, indicating the speed at which sound waves do work.
Under the same intensity, the higher the frequency of sound wave, the greater its power, so compared with sound wave, the power of ultrasonic wave is much greater than sound wave.
Extended data
When the ultrasonic wave propagates in the liquid along the gap of the liquid, the molecules of the liquid are transferred by the energy of the ultrasonic wave and have energy, and the interaction between the molecules produces a large number of bubbles. These bubbles constitute a prerequisite for cavitation. When the energy is gathered to a certain extent, the bubble bursts to generate huge energy, which wastes the whole liquid. Ultrasonic cleaning machines and small ultrasonic cleaning machines often use cavitation.
Ultrasonic wave has shorter wavelength than ordinary sound wave, better directivity and can penetrate opaque substances. This characteristic has been widely used in ultrasonic flaw detection, thickness measurement, distance measurement, remote control and ultrasonic imaging technology.
Ultrasonic imaging is a technology that uses ultrasonic waves to present the internal image of opaque objects. The ultrasonic wave emitted by the transducer is focused on the opaque sample through the acoustic lens, and the ultrasonic wave emitted by the sample carries the information of the irradiated part (such as the ability to reflect, absorb and scatter sound waves).
The acoustic lens converges on the piezoelectric receiver, and the obtained electrical signal is input to the amplifier. By using the scanning system, the image of the opaque sample can be displayed on the fluorescent screen.
Ultrasound has many applications in fisheries. It can be used for ranging, measuring speed, detecting obstacles, cleaning, welding, breaking stones, sterilizing and disinfecting, checking the defects of metal products, welding aluminum metal, washing clothes, drilling holes in inclined glass, looking for sunken ships, etc.
Baidu encyclopedia-ultrasound