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

Answer:

99.019 kPa

Explanation:

$P_a$ = Atmospheric pressure = 100 kPa

$\rho$ = Density of water in manometer = 1000 kg/m³

g = Acceleration due to gravity = 9.81 m/s²

h = Difference in height = 100 mm

As the pressure in the test section is lower than the pressure of the atmosphere it will be subtracted.

The absolute pressure in the test section is given by

$P_{ab}=P_a-\rho gh\\\Rightarrow P_{ab}=100\times 10^3-1000\times 9.81\times 100\times 10^{-3}\\\Rightarrow P_{ab}=99019\ Pa=99.019\ kPa$

The absolute pressure in the test section is 99.019 kPa