A anemometer It is a device used in the field of meteorology to measure the intensity of the wind .
The anemometers have several blades equipped with cups, which look like small metal bowls: when the wind blows, the anemometer blades begin to turn. The record of the number of laps allows to calculate the speed of the wind.
Anemometers of this type, which are also known as windlass anemometers , are the most used in the field of meteorology. Depending on the model, reading and recording the amount of laps that the wind produces in the small mill is carried out differently, and this also gives rise to different anemometer names. This variety is typical in inventions as old as this one.
In some cases, said value it 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 chart type recorder, it is called anemograph .
There are, however, other types of anemometers. In airplanes, anemometers equipped with a nickel or platinum thread which is heated by means of the electricity . The wind, by 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 slower by the molecules of air : the difference that is recorded between the relative radiation in the anemometer and the return of the radiation allows to estimate the speed that these air molecules have.
The device is also called anemometer, which, in airplanes, is used to calculate the travel speed. In this case, the anemometer has a different appearance and conception, and allows comparing the Pressure dynamic (that is, the impact of air) and the Static pressure through a pitot tube .
It is known as pitot tube to a combined outlet created in 1732 by the engineer Henri Pitot which serves to effect the calculation of the 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 It allows qualifying, according to the wind speed detected by the anemometer, if there is calm, breeze, strong, temporary wind or hurricane , among other states.
Approximately in 1805, the English naval officer and hydrographer Sir Francis Beaufort He 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 measurements They lacked objectivity.
Initially, the Beaufort scale did not have the different wind speed values, but indicated a series of terms qualitative according to the impact that they could have on the handling of vessels, and assigned them a number from zero to twelve, the smallest being "barely enough to perform maneuvers" and the largest, "impossible to hold for sails."
Over time, this scale became an essential part of the British Navy's logbooks and since the 1850s it transcended the limits of naval use, thanks to the association of its values with the number of rotations provided by the anemometer.