In fluid mechanics, pressure on a liquid can be influenced by various factors. When considering the total pressure on a liquid, atmospheric pressure is typically included. However, if we exclude the atmospheric pressure and only consider the pressure exerted by the liquid itself, we refer to this as gauge pressure.
Gauge pressure is the pressure relative to atmospheric pressure. It can be positive if the pressure is above atmospheric pressure or negative if below atmospheric pressure. The formula often used to measure it is:
[tex]\[ P_{\text{gauge}} = P_{\text{absolute}} - P_{\text{atmospheric}} \][/tex]
where:
- [tex]\( P_{\text{gauge}} \)[/tex] is the gauge pressure,
- [tex]\( P_{\text{absolute}} \)[/tex] is the absolute pressure,
- [tex]\( P_{\text{atmospheric}} \)[/tex] is the atmospheric pressure.
To summarize, the pressure on a liquid that does not include atmospheric pressure is called gauge pressure.
