# Changes

## Péclet number (Pe) - Nishanth Saldanha

, 11:14, 15 February 2017
Definition
The Péclet number (Pe) is a dimensionless number that represents the ratio of the convection rate over the diffusion rate in the a convection-diffusion transport system. <sup>[1][2]</sup>
$Pe = \frac{(Convection \, rate)}{(Diffusion \, rate)} = \frac {UL}{D}$ U represents linear flow in a control volume, L represents the length scale of the flow and D is the diffusion constant. This number can also be represented as a ratio of diffusive to convective time scales.
$Pe = \frac{(Diffusion \, timescale)}{(Convection \, timescale)}$