Ludwig Prandtl was a physicist who introduced a dimensionless fluid property in convective heat transfer, which is the so-called Prandtl number. It is defined as the ratio of the momentum diffusivity to thermal diffusivity,

Timestamps:
00:00 Motivation
00:24 Introduction and definition
02:59 Physical definitions
06:53 Summary
08:19 References

Key words: Heat transfer, fluid mechanics, convection, momentum diffusivity, dimensionless number, thermal diffusivity, boundary layer thickness