anemometer distance from blades

[oregon wind]

I will be mounting an anemometer on the top of my tower above my blades.

Does anyone have any feedback as to how many feet the anemometer should be above the blades to not be affected by the blade turbulance and give an accurate reading?

The anemometer will be mounted above a 12' turbine.

[jondecker76]

It probably depends on what purpose the Anemometer will serve.

If you are looking for accurate logging, then it would be best on its own tower, away from any external disturbance.

If you are just looking to log windspeed for a general indication, or for an over windspeed protection of your turbine, I would mount it about 20% of the prop diameter away.

Also, it would be much easier to mount it on the tower below the wind - this is what I normally see on some very large installations.

[scottsAI]

oregon wind,

Up wind of the blades is a high pressure area, as down wind of the blades is low pressure area.

The turbulent area around the blades is Dependent on wind speed, And how close to the blades the pole will be.

Best way would be to test, long pole with bunch of streamers... or just pick a nice fudge factor and say one radius above the blades.

Will the pole will be at the rotation point? With a wind change a velocity input will be added to wind speed.

I like your idea, let us know how it works out!

Have fun,

Scott.

[Flux]

Strange place but if the anemometer is on the yaw axis it will probably read reasonably for normal purposes if it is half a blade radius above the top of the blades. Most of the expansion of the air column happens behind the blades.

Make its pole very rigid and be sure it cant hit the blades.

Not suitable for precision power measurements but likely as good as you can get without a separate up wind mounting. Better than below the blades where you have tower shadow from some directions.

Flux

[oregon wind]

Thanks all for your input!

I will give it a shot, I will make sure to tilt my pole going up to avoid the blades.