# Bernoulli's Equation

Written by Jerry Ratzlaff. Posted in Fluid Mechanics

The following assumptions must be met for the Bernoulli's equation to apply:

• The fluid must be incompressible, even though pressure varies, the density must remain constant.
• The streamline must not enter the boundary layer.  (Bernoulli's equation is not applicable where there are viscous forces, such as in the boundary layer.)

Abbreviated as $$Be$$

## formula

$$p \;+\; \rho gh \;+\; \frac {1}{2} \rho v^2 = constant$$

Where:

$$p$$ = pressure at the point

$$\rho$$ = density of the fluid at all points in the fluid

$$g$$ = gravitational acceleration

$$h$$ = height, the point above a reference plane

$$v$$ = fluid velocity