On heat transfer problems in viscous flow

Many problems of physical interest which are associated with the flow of a viscous fluid through a narrow channel require the determination of the temperature distribution throughout the field of flow. In general, such problems may be separated into one of three classifications. The first of these is characterized by the existence of a thermal boundary layer, the second by a temperature distribution independent of the coordinate across the channel, and the third by an intermediate type of temperature distribution. In the present paper a simple method for the classification of such problems is given, and techniques for solving some of the problems which arise in practice are discussed.