How to Measure Wind Speeds ?
It is pretty much predictable that you have stumbled upon the weather forecasting channel at some point in your life. The neat and clean host beautifully presents the current weather condition of your country and also the international one. They also explain the speed of the wind and give an estimation of the incoming breeze.
Nevertheless, have you ever given a thought about how the wind speeds are measured? It is not like a sprint that you can easily measure with a stopwatch, right! Winds are invisible and the speed fluctuates from time to time.
Luckily, with the change and upgrade of technology, scientists around the world have successfully invented devices like ‘anemometers’ that can easily measure the speed at any time period.
From the following article, you will find out about how you can measure it precisely without any hesitation. Read on to find out more.
This device is simply a generator that runs electrically and it is fixed inside a metal cylinder. There is also an axle that points upward from the cylinder and on the top portion of it, a couple of large-sized cups are installed. They can easily catch the incoming winds and spin the generator constantly.
You will also see an anemometer that uses propellers instead of the cups. They work in the same way and the results are similar to zero error. The latest one consists of a propeller along with a cup at each blade’s end. When the wind strikes the device, the cup spins and counts automatically the number of times it just rotated per second.
Likewise, with the innovation of the gadgets, a fan-like an anemometer is also invented which uses a fan instead of the propeller or cup. As the fan rotates due to the wind, the generator starts working immediately. There is a circuit that is connected to the generator which gives you the wind speed reading in a digital format.
The ultrasonic anemometer is built with two to three pairs of sound transmitters and receivers. These are all fixed carefully with each other at an angle of ninety degrees (right angle).
The transmitter will emit sound waves of high frequency and the receiver will catch it according to the speed of the sound. There are electronic circuits specially installed in this device so that it can measure and give you the accurate wind speed results.
Sometimes the wind will blow very fast and at some point, it might get slow. So, depending on its pace the speed of the sound wave will vary. The circuit then calculates the difference between the sound wave speed and uses that result to generate the wind speed.
Accordingly, the biggest advantage of this device is that you can easily use it in any season as there are no moving parts like the mechanical one. When a component rotates, it might show problem out of the blue but you won’t be facing this in case of the ultrasonic anemometer.
Laser anemometer basically uses a laser beam that gets split in half because of a mirror. The mirror is half coated with silver so that the light passes only from one way and the other portion gets reflected.
So, there will be two laser beams overall and one of them will be called a reference beam, which means that it will not be manipulated in any case. The other beam will be used for measurement purpose and it will be calculated when the wind hits it. After that, both the beams are combined to get the final output.
At the same time, you will find a change in the pattern of the laser beam and it is known as a ‘set of interference fringes’. Measure the separation of the fringes and you will find out how the beam got affected in the end.
Finally, use the beam (measurement one) to move through a chamber (a pipe, tube, etc.) where the air is in constant motion. Make sure you have adjusted all the settings beforehand to avoid any errors. In this way, you will be able to measure wind speeds effortlessly.
Doppler Radar Anemometer
The good thing about the Doppler radar anemometer is that you can use it to measure wind speed as well as its direction. You might have some curiosity about the direction that the wind is currently following in your location and this device will help you to achieve that.
This anemometer emits an infrared laser beam that gets divided into two beams as well. Like the laser one, the first beam is taken as a reference that will be used and compared with the second one. The most important part of the total measurement is based on the second beam because it will give you the final wind speed.
When the incoming wind hits the generated laser beam, the particle inside the beam changes the alignment. As a result, this causes its frequency to change. This total movement of frequency is known as the ‘Doppler shift’. With this result, the wind speed can easily be measured.
Hot-wire anemometer is very unique in a situation when you have to measure the wind speed. The reason is that this device measures the proportion of cooling that the wind generates on a particular object and uses that measurement to calculate the wind speed.
Inside the device, there is an electric piece of wire that remains heated when you activate it and the wind basically blows onto it. When the wind strikes the wire, the heated element gets cooled down at some point which causes the resistance (electrical) to change.
This change in resistance will determine the amount the wire had cooled and this can be measured with the help of a circuit named ‘Wheatstone bridge’. With this overall result, wind speed can be measured.
Pressure Tube Anemometer
This type of device is quite older compared to the other ones mentioned above. It consists of a vertical tube along with a horizontal tube that is inclined or curved at the top portion.
On the other hand, there is a membrane installed in the tube and it is considered as the heart of the device. When the incoming wind hits the horizontal tube, the membrane starts moving. All the readings will be taken by the pressure gauge which will determine the pressure and from that, you will be provided with the wind speed result.
- When you are ready to measure the wind speed, look for locations where the area is wider than usual. The place can be an open field or even your rooftop.
- Keep one thing in mind and that is about the path that the wind takes place. The air always moves from higher to lower pressure areas. If you are planning to stand in front of your home or even a tree, you should be thinking about a different approach because most of the incoming wind will get blocked, unfortunately.
Therefore, the smartest strategy will be to stand as further as possible from this kind of thing and take your measurement with full accuracy.
- During the time you are taking the reading, hold the device in a fixed position. Avoid shaking it constantly or else the reading might come out differently.
- Keep the kids out of reach during the time you are measuring. Just give them something they prefer so that they stay busy.
- If you are using the most common anemometer that is the mechanical one, it is obvious that the propeller or the fan will spin quite faster when the speed of the wind will be high.
Suppose the reading you take is quite lower than you were expecting in the first place, then you have to check whether the device is having any internal malfunctions or not. Show it to a professional if you are unable to detect any flaws.
- In case you don’t have an anemometer and on top of that, you are not finding it in your nearby electrical store, simply go for the option known as ‘Beaufort wind force scale’ reading. It will give you a factual measurement of the intensity of the wind on the basis of observed situations that happens at sea or land.
- You can measure the direction of the wind using a wind vane. If you look at it, you will find that one end consists of a little bit of heavy item and the other one contains a leveled or flat item with a big space. The wind will push the flat item because it is not that heavy as the other end. This will cause the vane to swing and puts it in a parallel direction to the wind.
There are actually lots of devices that can help you in measuring the wind speeds. So, do some research and buy a good quality anemometer.
Consult with the experienced users for a quick guideline and some mini advices. Share your knowledge with your family and friends.
Have a good day!