Bernoulli's equation
In fluid dynamics, Bernoulli's Equation describes the behavior of moving fluids along a streamline.

 v = fluid velocity along the streamline
 g = gravitational constant
 y = elevation in gfield
 P = pressure along the streamline
 ρ = fluid density
These assumptions must be met for the equation to apply:
 Inviscid flow  Viscosity (internal friction) = 0
 Steady flow
 Incompressible flow  ρ is constant
 The equation applies along a streamline.
The equation can be derived by integrating the
Euler equations along a streamline.