Some Variational Theorems for Non-Newtonian Flow

A new variational theorem is formulated which has as its Euler equations and natural boundary conditions all of the differential equations and boundary conditions of the boundary value problem under consideration. Other variational theorems, including the classical theorems of Helmholtz, follow from this fundamental theorem. Conditions under which the theorems obtained are minimum or maximum principles are discussed and application to non-Newtonian flow in a tube is made.