Computer Aided Hot-Wire Calibration

Abstract

The hot-wire anemometer is now still the most important instrument for measuring turbulent flow. However, the hot-wire output is nonlinear to the wind velocity and is affected by a variation in air temperature. Thus, we have devised the new method of hot-wire calibration by the aid of a computer. There are the following characteristics in this method: First, the calibration curve of the hot-wire output versus the wind velocity is simply determined using a method of three-point interpolation with high accuracy. Second, in place of using analog linearizer, the hot-wire output could be linearized on reference to a table located on computer-memory in real time. Last, the calibration curve could be immediately corrected by remeasuring only the output voltage in the free stream, whenever air temperature varies.