Question

A manometer that is filled with water (rho=1000 kg/m3) is connected to a wind tunnel to measure the pressure inside the test section. The other manometer is open to the atmosphere and the atmospheric pressure is 100 kPa. The difference in the manometer level is 100 mm. Determine the absolute pressure in the test section in kPa.

Answer 1

To develop this problem it is necessary to apply the concepts performed to the absolute pressure based on the reference pressure (atmospheric) and the pressure that is generated due to the height of the column of the measured liquid.

In mathematical terms the previous concept can be expressed as

$P_{abs} = P_{atm} -\rho gh$

Where

$P_{atm}=$Atmospheric Pressure

$\rho =$Density

g = Gravitational acceleration

h = Height

Our values are given as

$h = 10*10^{-3}m$

g = 9.8m/s

$\rho_{water} = 1000kg/m^3$

$P_{atm} = 100kPa$

Replacing we have then that

$P_{abs} = P_{atm} -\rho gh$

$P_{abs} = 100 -(1000)(9.8)(10*10^{-3})$

$P_{abs} = 99.9019kPa$

Therefore the absolute pressure in the test section is 99.9019kPa