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:
“In a number of other cultures, fathers are not relegated to babysitter status, nor is their ability to be primary nurturers so readily dismissed.... We have evidence that in our own society men can rear and nurture their children competently and that men’s methods, although different from those of women, are imaginative and constructive.”
—Kyle D. Pruett (20th century)