50 Years of the K-BKZ Constitutive Relation for Polymers
Figure 8
Differences in flow behavior of polyethylene melts in a 20 : 1 axisymmetric abrupt contraction at the same capillary wall shear stress of MPa (Bagley and Birks [94]): (a) branched LDPE, (b) linear HDPE. The flow is from top to bottom.