Euler number (physics)
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This article is about fluid flow calculations. For Euler's number, see e (mathematical constant).
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.
It is defined as
where
- ρ is the density of the fluid.
- p(upstream) is the upstream pressure.
- p(downstream) is the downstream pressure.
- V is a characteristic velocity of the flow.
Somewhat the same structure, but with a different meaning is the Cavitation number:
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
- ρ is the density of the fluid.
- p is the local pressure.
- pv is the vapor pressure of the fluid.
- V is a characteristic velocity of the flow.
[edit] See also
- Reynolds number for use in flow analysis and similarity of flows
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[edit] References
- Batchelor, G.K. (1967). An Introduction to Fluid Dynamics. Cambridge University Press. ISBN 0-521-09817-3
