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Calibration of anemometers using wind tunnel contraction

Paulo José Saiz Jabardo; André Barsaglini da Costa; Anthur Feriotti Rosa; Nilson Massami Taira; Alessandro Alberto Lima; Gabriel Borelli Martins; Gilder Nader

A Laser Doppler Anemometer was used to calibrate the pressure drop across a wind tunnel contraction resulting in a mean coefficient of discharge Cd=0,984 at the cost of a small increase in uncertainty. Using the pressure differential to calibrate larger meters allows simultaneous measurement of anemometer and reference velocity thereby reducing some blockage effects. Calibration of a cup anemometer with a frontal area 7% of the wind tunnel section shows that the blockage induced error in velocity calibration is of the order of 1%. The use of pressure differential of the wind tunnel contraction when calibrating large anemometers can therefore reduce global calibration uncertainty and increase laboratory productivity.

JABARDO, Paulo José Saiz; COSTA, André Barsaglini da; ROSA, Anthur Feriotti; TAIRA, Nilson Massami; LIMA, Alessandro Alberto; MARTINS, Gabriel Borelli; NADER, Gilder. Calibration of anemometers using wind tunnel contraction. In: CONGRESSO BRASILEIRO DE METROLOGIA, 7., 2013, Ouro Preto. Anais... 4 p.