Total pressure

In physics, the term total pressure may indicate two different quantities, both having the dimensions of a pressure:

• In fluid dynamics, total pressure ($p_0$) refers to the sum of static pressure p, dynamic pressure q, and gravitational head, as expressed by Bernoulli's principle:

$p_0 = p + q + \rho g z\,$

where ρ is the density of the fluid, g is the local acceleration due to gravity, and z is the height above a datum.

If the variation in height above the datum is zero, or so small it can be ignored, the above equation reduces to the following simplified form:

$p_0 = p + q\,$

• In a mixture of ideal gases, total pressure refers to the sum of each gas' partial pressure.