Introduction to Engineering Heat Transfer

Chapter 8 provides correlations that can be used to solve external flow forced convection problems where an external flow is defined as one where the boundary layer can grow without bound. For flow over a flat plate located sufficiently far from any other surface, the boundary layer is never confined by the presence of another object and therefore continues to grow from the leading edge to the trailing edge. An internal flow is defined as a flow situation where the growth of the boundary layer is confined; that is, the boundary layers can only grow to a certain thickness before being constrained. Internal flows are often encountered in engineering applications (e.g., the flow through tubes or ducts).