Different Types of anemometers

Anemometers come in a variety of forms, these are cup, vane and hot wire. Which you should select really comes down to your application and budget. The simplest type is the cup anemometer so lets start there.

Cup Anemometer

The cup anemometer consists of a vertical pole with four horizontal arms attached to the top. Cups are attached to the ends of the four arms, and the wind causes the cups to rotate the arms around the central pole. The cup anemometer is prone to friction, which makes it less accurate than the more advanced versions but they are the most popular type of anemometer for personal use.  A cup anemometer calculates the wind speed by multiplying the revolutions the cups take over 1 minute by the circumference of the circle the cups create.

Benefits of a Cup Anemometer

• Low cost

• Good for general purpose applications

• Extensive selection available

Negatives of a Cup Anemometer

• Less accurate than more advanced types

• Not effective when turbulence intensity is high or wind velocity is low

Vane Anemometer

The vane anemometer must be parallel to the direction of the wind in order to work properly. A wind vane, attached to the tail of the anemometer, is pushed around until the propeller is facing into the wind. The wind then turns the propeller, which rotates a mechanism that calculates the wind speed.

Benefits of a Vane Anemometer

• Generally less expensive than other more advanced types

• Wind speed, Volumetric flow rate may be calculated

• Most models have a separate vane probe to enable suitable positioning of the probe during measurement taking

Negatives of a Vane Anemometer

• They must face the direction of the wind in order to work properly

Hot Wire

Hot wire anemometers use a very fine wire heated up to some temperature above the ambient. Air flowing past the wire has a cooling effect on the wire. As the electrical resistance of most metals is dependent upon the temperature of the metal, a relationship can be obtained between the resistance of the wire and the flow velocity

Benefits of a Hot wire Anemometer

• Have extremely high frequency-response and fine spatial resolution

• Universally employed for the detailed study of turbulent flows, or any flow in which rapid velocity fluctuations are of interest

Negatives of a Hot wire Anemometer

• More expensive than other types of anemometers

• Delicate Probe