Hydrostatics: Manometer Example
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 Manometer Pressure Manometers measure a pressure difference by balancing the weight of a fluid column between the two pressures of interest. Large pressure differences are measured with heavy fluids, such as mercury (e.g. 760 mm Hg = 1 atmosphere). Small pressure differences, such as those experienced in experimental wind tunnels or venturi flowmeters, are measured by lighter fluids such as water (27.7 inch H2O = 1 psi; 1 cm H2O = 98.1 Pa). To calculate the pressure indicated by the manometer, enter the data below. (The default calculation is for a water manometer with a 10 cm fluid column, with the answer rounded to 3 significant figures.):
Inputs
 Height of fluid column, h: m in ft cm mm Fluid density, r: kg/m^3 lb/in^3 kg/l g/cm^3
 Manometer Pressure, Dp: 981  Pa Pa mmHg inH2O inHg ftH2O psi atm

 Equations used in the Calculation The pressure difference between the bottom and top of an incompressible fluid column is given by the incompressible fluid statics equation, where g is the acceleration of gravity (9.81 m/s2).
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