# Prandtl number

From AMS Glossary

## Prandtl number

The nondimensional ratio between the product of heat advection and viscous forces and the product of heat diffusion and inertial forces in a given fluid.

It may be given as where

*C*_{p}is the specific heat at constant pressure, μ the dynamic viscosity, and*k*the thermal conductivity. The Prandtl number may also be defined as the ratio of the Reynolds to the Péclet numbers, or as the ratio of kinematic viscosity to thermometric conductivity.