ABSTRACT
This chapter describes the Reynolds transport theorem by deriving equations of compressible and incompressible flows. It applies the Reynolds transport theorem to an arbitrary control volume for the conservation of energy. The boundary layer theory was first conceptualized by Prandtl in 1904. The chapter derives boundary layer equations using order of magnitude analysis. The Prandtl number varies in a wide range from value of order of 0.01 for liquid metals to a value of order of 1000 for viscous oils. Simplifications are possible for very small or very large Prandtl numbers. The chapter also derives the non-dimensional form of the thermal boundary layer equation in the presence of viscous dissipation.
