In the early 19th century, a young Austrian man was strolling alongside a railway when a train passed by on the tracks beside him, and unlike usual, the young man noticed that the magnitude of the train's sound changed in the process. Upon returning to his home, he tried to develop a hypothesis and step-by-step proof of it, and then published a paper many years later establishing that the wavelength of an object's radiation varies with the relative motion of the source and the observer, a young man whose name was Doppler.
Just like that train, Doppler's scientific achievements skyrocketed him to fame, and despite his untimely death at the age of 49, he has made it possible for the name Doppler to still be remembered even 160 years later, and the physics effects that bear his name are widely used in today's society in all major fields such as healthcare, security, transport and communications.
On 24th March 2014, Malaysia Airlines MH370 was lost, and the whole world was concerned about this incident, and the search of more than ten countries around the world for nearly two weeks had no result, and when all the major countries were at their wits' end, some people used Doppler's effect to infer for the first time that the location of the lost plane was in the Indian Ocean, and one year later, the search team found the wreckage belonging to the lost plane on the French island of La Réunion in the Indian Ocean. Although there is still some error, the Doppler effect has solved the problem that all cutting-edge technologies could not cross five years ago.
The Doppler effect has brought great help to our life, everywhere we can see the radar speedometer to judge the speed of vehicles according to the frequency change of the vehicle emission; through the application of ultrasound in the body, so that we can grasp the state of the blood flow in the body at all times, so as to check out the heart, the brain and blood vessels of the disease; in the cosmic space which is difficult for us to reach, the Doppler effect makes us able to detect the movement of celestial bodies from the distance of the earth arbitrary The Doppler effect allows us to detect the trajectories of celestial bodies at any distance from the Earth. For human society, Doppler is the key to all moving objects.
Audiowell has introduced a product that utilises the Doppler effect - the Doppler Flow Sensor (US0055). The principle of this sensor is to capture the frequency changes emitted by flowing water to determine the speed of the water flow as well as the flow rate. Unlike conventional flow meters, the Doppler effect sensor uses non-contact measurement and is mounted on the outside of the pipe, which greatly reduces the difficulty and cost of installation.
In a pipe, water flows along a fixed track and direction, like a never-ending train. All moving objects in the universe are not Doppler's train, travelling slowly under the watchful eye of a wise man.
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