How Do You Convert mm of Head into Pascals for Aerodynamics Testing?

[escobar147]

Referenced pitot pressure = 107 (mm) referenced static pressure = 525 (mm)...
find referenced dynamic pressure by subtracting static pressure from pitot pressure and converting to Pascals...

how on Earth do you convert it to pascals?

 

[berkeman]

Referenced pitot pressure = 107 (mm) referenced static pressure = 525 (mm)...
find referenced dynamic pressure by subtracting static pressure from pitot pressure and converting to Pascals...

how on Earth do you convert it to pascals?

They are just two measurements of pressure... mmHg and Pascals:

http://www.unit-conversion.info/pressure.html

.

 

[escobar147]

They are just two measurements of pressure... mmHg and Pascals:

http://www.unit-conversion.info/pressure.html

.

is it not head?

 

[berkeman]

is it not head?

What is the definition of "head" in the context of this problem?

 

[escobar147]

What is the definition of "head" in the context of this problem?

it's the measurement of wake traverse behind anaerofoil, the pitot static tube is upstream and connected to a manometer, whilst the rest are pitot (stagnation) tubes and are located downstream and also connected to a manometer

 

[berkeman]

it's the measurement of wake traverse behind anaerofoil, the pitot static tube is upstream and connected to a manometer, whilst the rest are pitot (stagnation) tubes and are located downstream and also connected to a manometer

And the tubes all measure air pressure, correct?

 

[escobar147]

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