What does the term "gauge pressure" refer to in fluid dynamics?

Gauge pressure refers to the measurement of pressure relative to the atmospheric pressure surrounding a fluid system. It is the pressure indicated on a gauge that does not account for atmospheric pressure; thus, it reflects the difference between the pressure in a system and the ambient atmospheric pressure.

This concept is important in fluid dynamics and engineering because it allows for the measurement of pressure in systems where the atmospheric pressure may vary. For instance, if a gauge reads 10 psi, this indicates the pressure is 10 psi higher than the current atmospheric pressure.

Understanding gauge pressure is essential for various applications, including hydraulic systems, pneumatic systems, and various industrial processes, as it helps in monitoring system performance and safety without the complicating factor of atmospheric pressure variations.