Rotating vane anemometers are used to measure airflow in many engineering applications, especially in field applications such as volumetric airflow rate measurement for HVAC testing and balancing. It has been well documented that the accuracy of measurements made by rotating vane anemometers is affected by a number of factors. However, it is unclear as to how the level of turbulence intensity in the flow field affects the vane anemometer readings. This paper presents experimental results for the determination of the influence of various levels of turbulence intensity on the ability of rotating vane anemometers to accurately measure average air speed. Results are given for two different sizes of rotating vane anemometers covering a range of air speeds and turbulence intensities. Measurements from each rotating vane anemometer are compared with the associated measurements obtained using a thermal anemometer system equipped with a single sensor hot-film probe and a thermocouple for temperature compensation. Local velocity profiles and turbulence intensity information directly upstream of the test vane anemometer were obtained using the temperature-compensated hot-film probe. Based on the results presented in this article, turbulence intensity has been shown to significantly affect the accuracy of measurements made using rotating vane anemometers of either size.

Units: I-P