Question: Prandtl numbers are named after a pioneer in what applied science?

Related documents: [0]  [DOC] 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: [END] 
[1]  [DOC] Ludwig Prandtl (4 February 1875 – 15 August 1953) was a German engineer. He was a pioneer in the development of rigorous systematic mathematical analyses which he used for underlying the science of aerodynamics, which have come to form the basis of the applied science of aeronautical engineering. In the 1920s he developed the mathematical basis for the fundamental principles of subsonic aerodynamics in particular; and in general up to and including transonic velocities. His studies identified the boundary layer, thin-airfoils, and lifting-line theories. The Prandtl number was named after him. [END]  
Answer: aeronautical engineering
aeronautical engineering