# Hydrodynamic pressure

From AMS Glossary

## hydrodynamic pressure

The difference between the pressure and the hydrostatic pressure.

This concept is useful chiefly in problems of the steady flow of an incompressible fluid in which the hydrostatic pressure is constant for a given elevation (as when the fluid is bounded above by a rigid plate), so that the external force field (gravity) may be eliminated from the problem. If

*p** is the hydrodynamic pressure, ρ the density, and*V*the speed, Bernoulli's equation gives*See also*static pressure.