Uncertainty and Correction Methods of Wind Direction Anemometers
Wind direction and speed are important components of natural climate, and their existence not only reflects the characteristics of atmospheric circulation, but also serves as parameter indicators and energy sources for climate comparison in different places. The observation of wind speed and direction is inevitable due to the differences in equipment, observation methods, and measurement principles between the use of wind direction anemometers and manual methods. So the magnitude and reasons for this difference are worth exploring.
With the changes of the times, the development of wind direction anemometers is rapid. New instruments in various industries in China, especially wind direction anemometers, are an important task for predicting national weather and oceans. In order to ensure the traceability and quality assurance of reliable data measurement of wind direction anemometers, it is necessary to calibrate the instruments, especially under dynamic conditions, in wind tunnels.
The uncertainty of the wind direction and anemometer relative to the standard wind speed of the entire device should include the uncertainty of the measurement results of the standard instrument composed of a second class standard pitot static pressure tube and a micro pressure gauge, the uncertainty caused by the instability and non-uniformity of the airflow in the wind tunnel, and the uncertainty of the installation.
Calibration method for wind direction and anemometer
(1) Only wind direction anemometers that pass the appearance inspection can undergo the following calibration.
(2) The installation position and requirements of the pitot tube and wind direction anemometer in the wind tunnel calibrator: the total pressure hole of the pitot tube should be aligned with the direction of the airflow, the axis of the pitot tube probe should be (25 ± 5) mm away from the working section wall, and the pitot tube support rod should be vertically and firmly installed on the working section wall of the wind tunnel.
During the application process of the wind direction anemometer, the protective layer should be strong and uniform, and there should be no delamination. Obvious defects such as rust should appear. The installation and use should strictly follow the requirements of the user manual for correct installation to avoid increasing data errors. The application of wind direction and anemometer in agricultural production plays an important role in early prevention and protection of crops.
