June 2009
Please note the style followed in Physical Review E for fluid dynamics notation.
The following double-letter symbols are acceptable and should be defined at their first occurrence; they are set roman:
| Al | Alfvén number |
| Bi | Biot |
| Ca | Capillary |
| Co | Cowling |
| De | Deborah |
| Ec | Eckert |
| Eu | Euler |
| Fo | Fourier |
| Fr | Froude |
| Gr | Grashof |
| Ha | Hartmann |
| Kn | Knudsen |
| Le | Lewis |
| Ma | Mach |
| Nu | Nusselt |
| Pe | Péclet |
| Pr | Prandtl |
| Ra | Rayleigh |
| Re | Reynolds |
| Ri | Richardson |
| Rm | Magnetic Reynolds |
| Sc | Schmidt |
| Sr | Strouhal |
| St | Stefan, Stanton |
| Ta | Taylor |
| Ur | Ursell |
| We | Weber |