Archimedes number
The Archimedes number is named after the Greek Archimedes.
In viscous fluid dynamics, the Archimedes number (Ar) [1] is used when the motion of fluids is affected by density differences. It is a dimensionless number, the ratio of gravitational forces to viscous forces.[2]
The relationship and has the form:[3]
where:
- is the local external field (for example gravitational acceleration), m/s2,
- is the density of the fluid, kg/m3,
- is the density of the body, kg/m3,
- is the dynamic viscosity, kg/ms,
- is the characteristic length of body, m.