How are wind speeds measured?

Meteorologist Grant Gilmore explains how anemometers measure wind speeds.
Subscribe at: on.wtsp.com/youtube
Find WTSP online: www.wtsp.com/
Like WTSP on Facebook: / 10newswtsp
Follow WTSP on Twitter: / 10newswtsp

[@mulatubedada9153]

this is helpfull for kids and adults

[@user-sm4sf4ff2i]

Cheer~~~an instrument for measuring the speed of the wind, or of any current of gas.

[@spacebatstuckonearth8888]

but i bet how light or heavy the anemometer frames and cups materials are, the spin speed will vary and so how does that work out universally ?

[@JP-pb4tk]

The moment of inertia would not matter so long as the system is operating at steady state with an ideal bearing.

[@cappadon1986]

That is nice

[@titikshasoni4708]

What would happen if we change the directions of the cups? And why?

[@tofo2]

But wait!
The cup has a drag coefficient 0.38 from the convex side and 1.42 on the concave.
Drag: en.wikipedia.org/wiki/Drag_coefficient
The anemometer will accelerate until cups moving upstream balances the torque of the cups moving downstream.
It means the downstream cup has to gradually move slower than the wind until it produces a drag force large enough to push the more aerodynamic convex side of the cup upstream. If the downstream cup slows down it gets more drag while the upstream slows down and feels less drag.
If cup moves downstream with speed y the cups on the upstream side moves with speed -y
If the wind has the speed x, the cup downstream will feel a relative wind x-y and the one moving upstream x+y.
So the equilibrium is simply described by requiring magnitude of forces on opposite sides to balance out 1.42*(x-y)^2 = 0.38*(x+y)^2
The solution of the equality is satisfied at a straight line y = 0.32x
It means the cups reach equilibrium speed y at a factor 0.32 of the wind speed x.
In other words cups speed always adjusts to 32% of the wind speed.
At a wind of 5 m/s the cup moves at 1.574 m/s and is exposed to 3.409 m/s tail and 6.590 m/s head wind respectively. The shape evens out the game and they produce similar drag force.
~ 1.42*(3.409)^2 = 16.502 and ~ 0.38*(6.590)^2 = 16.503
Never lie to children.
en.wikipedia.org/wiki/Anemometer

[@NeilMarcellini]

Dude! Thank you so much! I had an intuition that the cups would not move at exactly the speed of the wind, and your explanation of drag coefficients and the equilibrium equation makes perfect sense. So, if an anemometer has had it's drag coefficient measured accurately, will the anemometer be perfectly accurate assuming the cup speed is multiplied by (in this case) 0.32? Are there any other factors that can affect accuracy?

[@tofo2]

​@@NeilMarcellini The calculation is not exact as the cups present different drag as they change angle, move in a circular path and wind is disturbed.
But as arm length is greatest when cups expose their basic shape the calculation will probably be quite good.
The forces on the cups vary with v square so high relative wind speed part of the motion will dominate.

[@Zack-xz1ph]

he wasn't lying, he was simplifying. there's a big difference

[@unkown6147]

Now how do I build one

[@user-jj8cp9go6m]

th-cam.com/video/FksecVcwj9A/w-d-xo.html

[@DamadGamer]

Take a pencil attach a few cups

[@juanleiba5686]

good video the anemometer is like a windmill

[@windspeedmetersandanemomet6444]

✔ SUPER INFO

[@masterx8963]

wave =atomsphar win dc gentor cons run light

[@stellareggiembiza2327]

🤩

[@rajeshwari7660]

Tq

[@ABMHosneeMobashir]

Hoga

[@unleashingtheself4443]

Too short video .. put more details please

[@shadaimartin9004]

Barometer and the others

[@ahmetylmaz9492]

Thanks (1.36).

[@ronaldworley7178]

Anemometers are god

[@mrs.vhorton8045]

I’m sorry, but his explanation was terrible