# Static Pressure vs Hydrostatic Pressure

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 August 12, 2014, 13:30 Static Pressure vs Hydrostatic Pressure #1 Senior Member   Join Date: Aug 2014 Posts: 160 Rep Power: 11 Hello, I know it's a basic question but I don't understand the difference between static Pressure which is defined as the pressure of the fluid at one point and hydrostatic pressure which is defined as the pressure in a fluid due to the weight of fluid above it. In my head, the static pressure in one point of fluid depend on the height of fluid above it but this is the definition of hydrostatic pressure. I am confused, I searched more information on internet but there is no clear answer about it. Can somebody please explain it to me ? Thank you very much for your help.

 August 12, 2014, 14:35 #2 Senior Member   Join Date: Jun 2009 Posts: 1,825 Rep Power: 33 Perhaps it is better to understand the different qualifiers, and then combine them Relative Value = Absolute Value - Reference Value Then, Relative Pressure (or Gauge Pressure) = Absolute Pressure - Reference Pressure. Total (or Stagnation) Value = Static (local conditions) Value + Dynamic Contribution. Then, for incompressible flows we could write (Absolute/Relative) Total Pressure = (Absolute/Relative) Static Pressure + 1/2 * Density * Velocity^2 For incompressible flows, Hydrostatic Pressure = density * gravity . ( position vector - reference location) I have not included moving frame quantities such as Stationary Frame (Absolute/Relative) Total Pressure. Expressions for compressible flows are not as simple, but the meaning remains. Hope the above helps,

 August 12, 2014, 16:14 #3 Senior Member   Join Date: Aug 2014 Posts: 160 Rep Power: 11 Sorry, but I still don't understand the difference between static pressure and hydrostatic pressure :s

 August 12, 2014, 23:29 #4 Senior Member   Join Date: Jun 2009 Posts: 1,825 Rep Power: 33