3066 -- Velocity Variation Effects on a Rotating Vane Anemometer at Coil Faces PDF

Rotating vane anemometers have been used extensively for many years, particulary for low-speed situations in which the velocity pressure is extremely low. If properly used, they give all the precision ordinarily required in engineering practice. However, the use of the rotating vane anemometer at coil faces requires the use of a correction factor to be applied to the average determined face velocity. Results of this theoretical analysis show that the correction factor at coil faces can be above or below the ideal value of 1.0 with a typical range of 0.88 to 1.06. In addition, when the rotating vane anemometer is used at coil faces, it is very sensitive to its location in the airstream when there is a nonuniform velocity profile. Likewise, the rotating vane anemometer for this situation is very sensitive to nonuniformity in the velocity profile. The correction factor was also shown to be a function of the size of the anemometer head. The results in this analysis are strictly theoretical and part of an overall project for the experimental determination of correction factors. Experimental values of correction factors for use at coil faces will be presented at a later date.

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