A anemometer is a device that is used in the field of meteorology to measure the intensity of the wind.
Anemometers have several blades equipped with cups, which look like small metal bowls: when the wind blows, the blades of the anemometer begin to rotate. Registering the number of laps allows you to calculate the speed of the wind.
Anemometers of this type, which are also known as vane anemometers, are the most used in the field of meteorology. Depending on the model, reading and recording the amount of turns that the wind produces in the small mill is carried out differently, and this also gives rise to different names of anemometer. This variety is typical of inventions as old as this one.
In some cases, said value can be reflected directly on a counter, or printed on a strip of paper (which is called anemogram), and there are also absolutely electronic devices, which have digital screens to express the results. When the anemometer has a graphical recorder, it is called anemograph.
There are, however, other types of anemometers. In airplanes, anemometers equipped with a nickel or platinum wire which is heated by means of electricity. The wind, when cooling it, produces a change in its resistance. In this way, the current that runs through the wire is proportional to the speed reached by the wind.
There are devices of this class that appeal to a laser beam that is divided. The return of the laser to the anemometer is slowed down by the air: the difference that is registered between the relative radiation in the anemometer and the return of the radiation makes it possible to estimate the speed of said air molecules.
Also called anemometer to the device that, in airplanes, is used to calculate the speed of displacement. In this case, the anemometer has a different look and feel, allowing you to compare the Pressure dynamic (that is, the impact of the air) and the Static pressure through a pitot tube.
It is known as pitot tube to a combined socket created in 1732 by the engineer Henri Pitot that serves to carry out the calculation of total pressure (also called backwater, remnant or of stagnation), which is equal to the sum of the static and the dynamic.
It should be noted that the Beaufort scale makes it possible to qualify, according to the wind speed detected by the anemometer, if there is calm, breeze, strong wind, temporary or hurricane, among other states.
The Beaufort scale
In about 1805, the English hydrographer and naval officer Sir Francis Beaufort created the scale that bears his name; Until then, naval officers were restricted to the results of their own observations, which they carried out with some regularity, but were not based on any scale, and therefore their observations. measurements they lacked objectivity.
Initially, the Beaufort scale did not have the different values of the wind speed, but rather indicated a series of terms qualitative according to the repercussion that these could have on the handling of the boats, and assigned them a number from zero to twelve, the smallest being “barely enough to carry out maneuvers” and the largest, “impossible to hold for the sails.”
Over time, this scale became an essential part of the British Navy logs and since the 1850s it has transcended the limits of naval use, thanks to the association of its values with the number of rotations provided by the anemometer.