A new Study on the Cup-Anemometer. II

Abstract

From the previous investigation and others we got an idea that the logarithm of the true air speed can be expressed in an algebraic function of the third degree with respect to the logarithm of the rotating speed of anemometer-cup, that is, logV=α+βlogμ+γ(logμ)²+δ(logμ)³, which has an inflexion point.
Taking the Kew Standard nine-inch-cup anemometer as an example, we tried to express our idea substantially, and obtained a fair result, which has small error.
From this formula we can derive another one for the variable factor of the anemometer. It is worth to notice that the latter expression has a maximum and a minimum.