Euler Number
Introduction to the Euler Number used in fluid mechanics.
The Euler Number is a dimensionless value used for analyzing fluid flow dynamics problems where the pressure difference between two points is important. The Euler Number can be interpreted as a measure of the ratio of the pressure forces to the inertial forces.
The Euler Number can be expressed as
Eu = p / (ρ v^{2}) (1)
where
Eu = Euler number
p = pressure (Pa)
ρ = density (kg/m^{3})
v = fluid flow velocity (m/s)
The pressure difference is often used
Eu = dp / (ρ v^{2}) (2)
where
dp = differential pressure (Pa)
 Note!  a perfect frictionless flow corresponds to that the Euler number equals 1
The combination below is called the pressure coefficient
pressure coefficient = dp / (1/2 ρ v^{2}) (3)
A special version of the Euler Number is in general referred to as the Cavitation Number.
Related Topics

Fluid Mechanics
The study of fluids  liquids and gases. Involving velocity, pressure, density and temperature as functions of space and time.
Related Documents

Cavitation Number
An introduction and definition of the Cavitation Number. 
Dimensionless Numbers
Physical and chemical dimensionless quantities  Reynolds number, Euler, Nusselt, and Prandtl number  and many more. 
Pressure Coefficient
The Pressure Coefficient is the ratio of pressure forces to inertial forces.