Relations between Certain Non‐Viscometric and Viscometric Material Functions

The case of nilpotency of order two has been studied extensively as viscometric flows, and the case of a symmetric L has been examined as elongational flows. Recently, ex amples of motions with L being nilpotent of order three and not two, and not nilpotent and not symmetric, were given by the author. It is the purpose of this paper to select an example of a motion from each of these two categories and to relate the material functions in these two nonviscometric motions with constant stretch history to the viscometric material functions of the incompressible simple fluid, bytreating the flows as nearly viscometric flows in the sense of A. C. Pipkin and D. R. Owen. The response of the incompressible simple fluid in these two flows is then compared to that of the BKZ fluid.