berkeman said:
And the tubes all measure air pressure, correct?
An aerofoil (chord c = 0.152 m; span b = 0.30 m; NACA 0012 section) is mounted in a drag
balance. A comb of Pitot and static tubes is mounted downstream of the aerofoil. Tubes
numbered 5, 12, 21 and 28 measure static pressure, while the rest measure Pitot (stagnation)
pressure. The tubes are connected to a multi-tube manometer, leaving four spare manometer
tubes (33-36). A Pitot-static tube is provided upstream of the model to measure free-stream
conditions and its two connections should be connected to two of the spare manometer tubes.
The manometer should be set at a low inclination (20º to the horizontal). Note that the
manometer is graduated in centimetres and contains fluid of specific gravity 0.784.
Measurements
(1) As in Part I, read the laboratory barometer and thermometer to determine the air
density and viscosity.
(2) With the wind tunnel running at maximum speed (both fans on), take the reference
pitot pressure (p0,ref) and static pressure (pref) upstream and convert the difference
from mm to Pa, noting the sign! Deduce the free-stream dynamic pressure
