Anemometer - the application of wind speed sensor in the field of aviation
The "pitot tube" on the aircraft is a typical pitot tube wind speed sensor and is an extremely important measurement tool on the aircraft. Its installation location must be in an area outside the aircraft where the airflow is less affected by the aircraft, generally directly in front of the nose, vertical tail or wingtips. When the aircraft is flying forward, the airflow rushes into the pitot tube, and the sensor at the end of the tube will sense the impact force of the airflow, that is, the dynamic pressure. The faster the plane flies, the greater the dynamic pressure. If you compare the pressure when the air is still, that is, the static pressure and the dynamic pressure, you can know how fast the air is rushing in, that is, how fast the plane is flying. The tool for comparing the two pressures is a hollow circular box with corrugated surface made of upper and lower two very thin metal sheets, called diaphragm box. The box is sealed, but has a tube connected to the pitot. If the speed of the aircraft is fast, the dynamic pressure will increase, the pressure in the bellows will increase, and the bellows will bulge. A device composed of small levers and gears can measure the deformation of the bellows and display it with a pointer. This is the simplest airspeed indicator for an aircraft.
The static pressure measured by the pitot tube can also be used as a calculation parameter for the altimeter. If the bellows is completely sealed, the pressure inside will always be equal to the pressure of the ground air. In this way, when the aircraft flies into the air, the altitude increases, and the static pressure measured by the pitot tube decreases, and the bellows will bulge, and the height of the aircraft can be measured by measuring the deformation of the bellows. This type of altimeter is called a barometric altimeter.
The speed measured by the pitot tube is not the real speed of the aircraft relative to the ground, but only the speed relative to the atmosphere, so it is called airspeed. If there is wind, the speed of the aircraft relative to the ground (called ground speed) should also be added to the wind speed (flying with the wind) or subtracted from the wind speed (flying against the wind).
With the development of modern science and technology, some new wind speed sensors such as lasers have also begun to be used in wind speed detection. It is believed that in the near future, various new wind direction and speed sensors will be more and more used in construction machinery, railways, ports, docks, power plants, meteorology, cableways, environment, greenhouses, farming and other fields.
flying downwind) or minus the wind speed (flying upwind).
