2011 Volume 39 Issue 3 Pages 105-111
Shear banding emerges in shear flows of wormlike micelle solutions and is observed as band velocity profiles in velocity measurement experiments. In our previous experiments, multi-band velocity profiles were captured in shear flows of a CTAB/NaSal solution between parallel plates. The relationship between the band velocity profile and the micellar network structure is an interesting issue. In the present study, the orientation behavior of the micelle network was numerically analyzed using a network scission model. Brownian dynamics simulations were carried out for a two-species model of micelle networks derived in the Vasquez-Cook-McKinley model. The numerical results indicate that the effect of the orientation of short micelles on the behavior of the entire system is small, whereas long micelles tend to align well in the flow direction, their degree of orientation is relatively high, and their orientation behavior strongly affects the orientation of the entire system. Numerical analysis using the BD simulation provides useful information on the flow-induced structures of the micelle network, and hence the present approach is effective for the analysis of the mechanism of shear banding.
