Prandtl numbers are named after a pioneer in what applied science?
Prandtl number The Prandtl number (Pr) or Prandtl group is a dimensionless number, named after the German physicist Ludwig Prandtl, defined as the ratio of momentum diffusivity to thermal diffusivity. That is, the Prandtl number is given as:
Ernst Engel Ernst Engel (March 26, 1821 – December 8, 1896) was a German statistician and economist, famous for the Engel curve and the Engel's law.