  A new approach to the study of similarity of temperature profiles is
presented. It is applicable for any 2-D fluid flow along an isothermal heated
(cooled) wall. The approach is based on a simple concept; the area under a set
of scaled temperature profile curves that show similar behavior must be equal.
This leads to a new integral-based definition of temperature profile
similarity. By taking simple area integrals of the scaled temperature profile
and its first derivative, we also obtain a number of new results pertaining to
similarity of the temperature profiles. For example, it is shown that if
similarity exists, then: 1) the similarity temperature and length scaling
parameters are interdependent, 2) the thermal displacement thickness must be a
similar length scaling parameter, and 3) the temperature scaling parameter must
be proportional to the free stream minus wall temperature values.
