Prandtl number
= Prandtl number
{c}
{title2=$\operatorname{Pr}=\nu/\kappa_T$}
{wiki}
The <Prandtl number> is the ratio of <kinematic viscosity> to <thermal diffusivity>. It compares the rates at which momentum and <temperature> variations diffuse. In thermal-diffusion units the <Boussinesq equations> have momentum inertia multiplied by $\operatorname{Pr}^{-1}$; large, rather than small, <Prandtl number> supplies the usual instantaneous <Stokes flow> limit.