The Euler number is a dimensionless number used in fluid flow calculations. It expresses the relationship between a local pressure drop e.g. over a restriction and the kinetic energy per volume, and is used to characterize losses in the flow, where a perfect frictionless flow corresponds to an Euler number of 1.
It is defined as
where
- is the density of the fluid.
- is the upstream pressure.
- is the downstream pressure.
- is a characteristic velocity of the flow.
The cavitation number has a similar structure, but a different meaning and use:
The Cavitation number is a dimensionless number used in flow calculations. It expresses the relationship between the difference of a local absolute pressure from the vapor pressure and the kinetic energy per volume, and is used to characterize the potential of the flow to cavitate.
It is defined as
where
- is the density of the fluid.
- is the local pressure.
- is the vapor pressure of the fluid.
- is a characteristic velocity of the flow.
Famous quotes containing the word number:
“Black lady,
what will I do
without your two flowers?
I have inhabited you, number by number.
I have pushed you in and out like a needle.”
—Anne Sexton (1928–1974)