A
dimensionless number used in
fluid dynamics as a measure of the
ratio of
pressure forces to
inertial forces, often written in terms of a pressure difference, Δp.
EU = p / (ρ v2)
p = pressure (or Δp = pressure difference), ρ = density, v = velocity
The Euler number was named for the famous Swiss mathematician Leonhard Euler. Some form of the Euler number is usually found in problems where pressure (or pressure differences) is important.
Two other variants of the Euler number (both dimensionless) are:
Pressure coefficent = Δp / (½ ρ v 2)
and the Cavitation number.
also see
Dimensionless numbers and
Buckingham Pi Theorem