Let us examine the transport peoperties,
are constants then
| Property | Unit | | Air | Water | Oil | Hg |
| | | | | | | |
| | | 0.5 | 1.2 | | | |
| | | | | | | |
| | | | | | | |
| k | | | | | | |
| | | | | | | |
| Pr | 0.95 | 0.71 | 7 | 5000 | 0.029 |
where
is the kinematic viscosity,
is the thermal diffusivity and Pr is Prandtl number.