AbstractThe hydrodynamics of the filling of a rectangular mold cavity by a molten polymer is considered in terms of lubrication theory. Both isothermal and nonisothermal mold filling are analyzed. The relationship of the velocity field to the cavity geometry and temperature dependence of the rheological properties is predicted. Increasing the activation energy of viscous flow increases the tendency for channeling of melt through the center of the cavity. The results are compared to the experimental observations of our previous studies.