An anemometer is a wind measurement tool that measures wind direction, amplitude, intensity and speed. Meteorologists frequently use this method to examine weather conditions. Physicists use it to consider the path of airflow. The first ones have constructed hundreds of years ago to estimate wind measurement. They come in both manual and digital versions and may be used to determine gas velocity and velocity in unconfined and enclosed flows, such as ambient wind. 

Anemometers are available in a variety of shapes and sizes. Some are portable handheld anemometers, while others are fixed within and attached to buildings as part of weather stations. 

The typical anemometer can contain four cups to measure the wind speed. The horizontal arm is joined to each of these four. The more wind there is, the quicker the cups spin the axis. The wind speed is measured in revolutions per minute (rpm). Modern anemometers, as well as other pocket-sized gadgets, have a distinct appearance.

To measure wind speed, one can obtain the reading by taking the anemometer outside. Then, throughout the next 30 seconds, count how many times the cup passes in front of you. To get rotations per minute used to calculate the speed of the win, multiply it by two. Wind speed will be stated in rpm in this manner.

What is the working principle of an anemometer?

The working principle of an anemometer can be stated as follows – 

It operates on the conversion of mechanical energy into electrical energy. Because the airflow speed regulates the cooling rate, the air stream will cool a hot object. Within the airflow, a fine wire that has been electrically heated can be positioned. So, as soon as the airflow rises, the wire becomes cold.

What are the advantages of using an anemometer?

• Extremely precise.
• It demands low power consumption.
• The user may measure numerous wind characteristics with one gadget, including wind pressure, direction, velocity and speed.
• It is available in a variety of sizes and forms.
• This climate station can detect, estimate, and give all wind-related information.

Types of Anemometers

There are four types of anemometers, each with its own set of features and applications.

Cup Anemometer

Three to four cups are usually joined to horizontal arms set on a vertical rod in cup anemometers. The cups spin freely as the wind speed increases. A hall effect sensor, also known as a reed switch, counts the number of revolutions in a certain period of time and translates the number of rotations into a wind speed metre.

Vane Anemometer

Vane anemometers use propellers or turbines to measure wind speed. For instance, a propeller blade may include a magnet that passes each time through a reed switch when the turbine rotates. The gadget counts how many times the magnetised blade passes over the reed switch in a certain amount of time and transforms it to a wind speed reading.

Hot Wire Anemometer

Hot Wire Anemometers use the principle that the colder the wind flow impact, the more heat it extracts. They utilise a tiny wire that has been heated to a few degrees above room temperature. The gadget will try to maintain a constant temperature for the wire while any air passing by will begin to cool it. The metre will then calculate how much current was required to maintain the wire’s temperature while also converting this metric to an air velocity value.

Laser Doppler Anemometer

It monitors the airflow’s instantaneous velocity. It offers several advantages. For instance, it is non-intrusiveness, does not require calibration, can monitor flow reversals, has high resolutions, measures accurately, and works for various applications. River hydrology and jet engines both utilise it extensively.

Ultrasonic Anemometer

This instrument consists of an ultrasonic sound receiver and emitter. They are placed in front of the sample volume. It uses an acoustic measurement approach to determine the factors related to the changes in the wind. It may be used in research and development, power plants and meteorology.

Pitot Tube Anemometer

These measure airflow temperature and velocity in the mid to high-velocity range. In most cases, a pitot tube has two openings. The first opening in the front receives the wind and calculates the stagnant pressure. The pitot tube’s second hole monitors static pressure and is situated on the side. The gadget calibrates the difference between these two pressures, converts it to dynamic pressure measurement, and then converts it to a wind velocity reading.

Anemometer Uses

Some of the most common anemometer uses are:

• An anemometer measures the wind parameter at nearly every weather station, from the hot equatorial to cold Arctic areas. 
• For climatologists, engineers and pilots, wind speed can help predict a shift in weather patterns, such as an oncoming storm.
• Aerospace engineers and physicists commonly use laser anemometers. 
• Laser anemometers are also used in velocity experiments. The direction and rate of change in an object’s location are measured by velocity. For instance, these anemometers calibrate the wind speed around spacecraft, aircraft and vehicles. 
• The cars are made more dynamic with the help of anemometers.

Conclusion

An anemometer is a tool for determining direction and wind speed. It is also the most frequent device used in weather stations. The word anemos is Greek in origin, and thus, the word anemometer is derived from it. The meaning of this word is wind. In meteorology, it also refers to any wind speed instrument. 

The anemometer is used to identify the strength of the wind, the direction of the wind and the airspeed.