The Giesekus model

(a) Use the results in Table 8.5-1 to get the limiting values for the non-Newtonian viscosity and the normal stress differences as the shear rate goes to zero.

(b) Find the limiting expressions for the non-Newtonian viscosity and the two normal-stress coefficients in the limit as the shear rate becomes infinitely large.

(c) What is the steady-state elongational viscosity in the limit that the elongation rate tends to zero? Show that the elongational viscosity has a finite limit as the elongation rate goes to infinity.