evotunedscc said:Currently I'm in Fluid Mechanics. In a homework problem I'm given the gage pressure inside of a piezometer. In my book there's an equation p(gage) = p - pa . What are the P and the Pa?
Gauge pressure is a measurement of pressure relative to atmospheric pressure, and is typically used for measuring small pressure differences. Pa (Pascal) is the SI unit for pressure and is used for measuring absolute pressure. P refers to pressure in general, and can refer to either gauge pressure or absolute pressure.
Gauge pressure is typically measured using a pressure gauge that is calibrated to read zero at atmospheric pressure. The gauge is then connected to the system or device being measured, and the difference between the atmospheric pressure and the pressure in the system is displayed on the gauge.
To convert gauge pressure to absolute pressure, you can use the formula P(abs) = P(gauge) + P(atm), where P(abs) is absolute pressure, P(gauge) is gauge pressure, and P(atm) is atmospheric pressure. This formula takes into account the fact that gauge pressure is measured relative to atmospheric pressure.
Some common units for measuring pressure include Pa (Pascal), bar, atm (atmosphere), psi (pounds per square inch), and torr (millimeter of mercury). It is important to pay attention to the units when working with pressure to ensure accurate measurements and conversions.
Understanding the difference between gauge pressure and absolute pressure is important because it can affect the accuracy and interpretation of pressure measurements. For example, if a pressure gauge is used to measure absolute pressure but is calibrated for gauge pressure, the reading will be incorrect. Additionally, different systems or devices may require different types of pressure measurements, so it is important to know which type of pressure is being used.