Examples of first normal-stress differences

Particular examples of the first normal-stress difference Ni or its coefficient are shown in figures 12 - 29, where a comprehensive collection of examples is given for polymer solutions and melts, as well as an emulsion. These are compared with either the equivalent shear stress or the viscosity. All the different possible combinations of shear and normal-stress difference, and viscosity and normal-stress coefficient are displayed to show the way that results are presented in the rheological literature. The figures are set out to illustrate overall behaviour, with especial emphasis on low shear-rate and mid-range (i.e. power-law) behaviour. 

F ure 18 The dscosity (dotted line) mid first normal-stress 

F ure 20 The shear stress (dotted line) d first luxin -stress 

F ure 21 The viscosity and first normal-stress difference coefficient (1st NSD) as a function of shear rate at room temperature for a solution of polyisobutylene in cetane, [12]. 

F ure 22 The viscosity (dotted line) and first normal-stress 

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