What is Fluid Pressure?

Pressure-Height Diagrams

In the expression, $P=\gamma h$. We can interpret one thing: as an object goes deeper into a fluid, it will experience more pressure.

We can represent this phenomenon using a pressure-height diagram.

• It is a Cartesian graph showing the plot of pressure versus height (depth)
• The origin is usually the surface of the fluid.
• Normally, we orient the graph differently; the depth $h$ is the y-axis while the pressure $P$ is the x-axis

Summary

Pressure $P$ is a perpendicularly-applied force $F$ per unit area $A$. It is similar to stress.

Standard units would be Pascal (Pa), pound-force per square inch (psi), atmospheres (atm), or specific manometric units such as (mmHg).

Pressure is the unit weight of the fluid $\gamma$ times height from a reference $h$: $P=\gamma h$.

In addition, it is the product of density, $\rho$, acceleration due to gravity $g$, and height from a reference $h$: $P=\rho gh$

As an object goes deeper into a fluid, it will experience more pressure. We can represent this phenomenon using a pressure-height diagram.