Mechanical MeasurementsAir Speed InstrumentsTechnical Contacts: Chris Crowley Please contact the technical staff before shipping instruments or standards to the address listed below. Mailing Address:
Fees are subject to change without notice. back to top of page | back to index of mechanical measurements Air Speed Instruments (19010C-19020C)The National Institute of Standards and Technology provides calibration services for air speed instrumentation such as Pitot tubes, hot-wire or thermal anemometers, ultrasonic anemometers, cup anemometers, propeller anemometers, and the like. The calibration service is performed in the dual test-section wind tunnel over a range of 0.15 m/s to 40 m/s (0.34 miles per hour to 80 miles per hour) with a test section of 1.5 m by 2.1 m (5 ft by 7 ft). The standard for air speed measurement at NIST is a fiber optic Laser Doppler Anemometer (LDA), which is calibrated with known velocities produced by a rotating disk. The air speed calibrations are done by direct comparison of the response of the instrument under test with the response of a NIST LDA. The uncertainty of the air speed standards shown in figure 1 as function of air speed is
Figure 1. NIST Air Speed Uncertainty versus Air Speed A normal air speed calibration consists of the average of ten independent measurements at seven to thirteen air speeds. Air Speed Special Tests (19030S-19040S)Special tests of airspeed instruments can be arranged. Examples include in-situ calibrations of airspeed instrumentation, proving other airspeed instrumentation, proving other airspeed measurement systems, and tests where appropriate scaling will allow the results to be applicable to fluids other than air, and wind speed and wind direction. Details can be obtained and arrangements made through the technical contacts cited above. back to top of page | back to index of mechanical measurements References-Airspeed MeasurementsUncertainty of NIST Air Speed Calibrations, T. T. Yeh and J. M. Hall, Proc. 2008 Meas. Sci. Conf., Anaheim, CA (2008). Airspeed Calibration Service, T. T. Yeh and J. M. Hall, NIST SP 250-79 (2007). New Primary Standards for Air Speed Measurement at NIST, V. E. Bean and J. M. Hall, Proc. 1999 NCSL Workshop and Symp. (Charlotte, NC: NCSL 1999). back to top of page | back to index of mechanical measurements Program questions: Calibrations Phone: 301-975-2200, Fax: 301-975-2950 NIST, |
(k=2), where V LDA is the velocity from the LDA in the unit of m/s. The air temperature, relative humidity, and atmospheric pressure in the wind tunnel during the calibration are also measured and recorded.