Facility for calibrating anemometers as a function of air velocity vector and turbulence

Published

July 19, 2021

Author(s)

Iosif Isaakovich Shinder, Michael R. Moldover, James Filla, Aaron Johnson, Vladimir B. Khromchenko

Abstract

NIST calibrates anemometers as a function of airspeed vector and turbulence intensity (Tu). The vector capability (sometimes called '3D') is particularly important for calibrating multi-hole differential-pressure probes that are often used to quantify pollution emitted by smokestacks of coal-burning electric power plants. Starting with a conventional '1D' wind tunnel, we achieved vector and Tu capabilities by installing translation/rotation stages and removable turbulence generators (grids or flags). The calibration ranges are: yaw angle ±180°; pitch angle ±45°; airspeed 1 m s−1 to 30 m s−1; turbulence intensity 0.07 ⩽ Tu ⩽ 0.25; average data collection rate: 300 points/h at fixed Tu. The system's expanded uncertainties corresponding to 95% confidence level are: airspeed 0.0045 × |V| + (0.036/|V|)2 where |V| is the magnitude of the airspeed in m s−1; pitch and yaw angles 0.3°; and turbulence intensity 0.03 Tu. The airspeed working standard is a laser Doppler anemometer that is traced to SI unit of velocity via a spinning disk. Calibrations are corrected for blockage by the instrument under test and its supports.

Citation

Metrologia

Volume

58

Issue

4

Pub Type

Journals

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Keywords

Airspeed vector calibration, blockage effect, hot wire probe, multi-hole pitot probe, turbulence correction, turbulent flow.

Citation

Shinder, I. , Moldover, M. , Filla, J. , Johnson, A. and Khromchenko, V. (2021), Facility for calibrating anemometers as a function of air velocity vector and turbulence, Metrologia, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=932052 (Accessed October 21, 2025)