Characteristic Numbers
Below is a list of the most important dimensionless parameters used in aerodynamics.
A list of all known parameters in the applied sciences (about 280 of them !) is
available in Ref. 1.
1. Reynolds number
Field of Use: Dynamic similarity
Field of Use: Compressible flows
3. Prandtl number
Field of Use: Convective heat transfer
4. Knudsen number
Field of Use: Hypersonic flows.
5. Strouhal number
Field of Use: Unsteady flows.
6. Froude number
Field of Use: Wave and surface flows
6. Reduced Frequency number
Field of Use: Dynamic Stall and other oscillatory flows.
7. Eckert number
Field of Use: High-speed flows with heat exchange.
2. Mach Number
Nomenclature
| a | = | Speed of Sound |
| g | = | Acceleration of gravity |
| u | = | Speed |
| L | = | Length Scale |
| k | = | Coeff. of Thermal Conductivity |
| V | = | Velocity |
 | = | Molecular mean path |
 | = | frequency |
Selected References
- Parker SP. (editor). Fluid Mechanics Source Book, McGraw-Hill, 1987 (ISBN 0-07-045502-3).