Monitoring principle of ultrasonic wind speed and direction transmitter

Monitoring principle of ultrasonic wind speed and direction transmitter

The vibration of the sound source body causes the air around it to alternately compress and expand, and gradually propagate outward, thereby forming a sound wave, whose unit is Hertz (Hz).

Generally speaking, the frequency of sound waves that can be heard by the human ear is about 20-20,000Hz. We call sound waves below 20Hz infrasound waves, and sound waves over 20,000Hz are called ultrasonic waves.

Ultrasonic has high frequency and high power, its energy is much larger than that of ordinary sound waves, and its wavelength is short, the diffraction is not serious, and it has good directionality, so it is widely used in industry and medicine. Today, let's talk about meteorological monitoring. How does ultrasonic monitor wind speed and direction.

A measuring instrument that calculates wind speed and wind direction by sending ultrasonic pulses and measuring the time or frequency (Doppler transform) difference at the receiving end. We call it an ultrasonic wind speed and direction transmitter, which is an application of ultrasonic detection technology in gaseous media. 

The propagation speed of sound in the air will be superimposed with the airflow speed in the wind direction; if the propagation direction of the ultrasonic wave is the same as the wind direction, its speed will be accelerated;

Conversely, if the ultrasonic wave propagates in the opposite direction to the wind, its speed will slow down.

Therefore, under the fixed detection conditions, the speed of the ultrasonic wave in the air can correspond to the wind speed function, and the precise wind speed and direction can be obtained by calculation.

Now with the development of science and technology, the commonly used wind speed and wind direction monitors in meteorological monitoring include arrow wind direction transmitter, three-cup wind speed transmitter and ultrasonic wind speed and direction transmitter.

Both the rotor type wind direction transmitter and the three-cup type wind speed transmitter are designed with mechanical structure, and there are rotating parts. Before monitoring, low wind speed is required to start. If the wind speed is lower than the start value, the propeller or the wind cup cannot be driven to rotate. monitoring; and because of its moving parts, it is easy to wear and be damaged by bad weather, so ultrasonic wind speed and direction transmitter is a good choice.