Response Characteristics and Meteorological Utilization of Propeller and Vane Wind Sensors

Abstract

The fundamentals of step and sinusoidal gust responses for propellers and vanes are considered, and methods and graphs are given for obtaining sensor characteristics from simple wind tunnel tests. Formulas are derived for predicting the response of propeller anemometers and direction vanes having either single tails or tails plus forward fins for better damping. The derivation for the vanes includes consideration of gust gradient effects. Two ways to match the low frequency phase lags of first and second order sensors are given. The principles are illustrated by detailed examination of a propeller anemometer mounted in front of a two-axis direction vane; the measured and calculated responses are compared. It is shown that the propeller response distance and the vane natural wavelength and damping ratio are all independent of wind speed. With the concept of an inertial subrange of eddy sizes over which the turbulent spectrum shape is known, the required sensor response characteristics for various types of wind measurements are examined.