UT Manometer Exercise Solution


Given: Px = -67.7 kPa
Py = atmospheric
gH2O = 9.798 kN/m3
gM = 132.836 kN/m3
Find: h



Solution:

Based on basic fluid statics principles:

P1 = Px + gH2O L + gM h

P2 = Py + gH2O (h + L)


Because P1 and P2 are at the same elevation and are within a continuous fluid, P1 = P2:

Px + gH2O L + gM h = Py + gH2O (h + L) = Py + gH2O h + gH2O L


Since the right-hand tank is open to the atmosphere, Py = 0.

Cancelling the gH2O L terms:

Px = gH2O h - gMh

h = Px/(gH2O - gM) = -67.7 kPa/(9.798 kN/m3 - 132.836 kN/m3) = 0.55 m

Since h is positive, the manometer fluid is higher on the left-hand side of the U-tube than on the right.



Plugging these values into the Manometer Applet yields:

h = 550 mm = 0.55 m

so the solution is correct!



Return to Manometer Exercise.

Return to Manometer Applet.