Role of slip velocity on peristaltic transport of couple stress fluid through an asymmetric non-uniform channel: Application to digestive system

Of concern in this paper is an investigation of peristaltic transport of a couple stress fluid in an asymmetric and non-uniform channel under the action of an externally applied magnetic field. The study is motivated towards investigating the peristaltic mechanism in the digestive system by considering the particle size effects. The effects of slip velocity on the channel walls have been taken into account. The nonlinearity of the problem is analyzed by using the long wave length and low Reynolds number approximations. The mathematical expressions for axial velocity, stream function, pressure gradient and pressure rise per wave length have been derived analytically. The above said quantities are computed for a specific set of values of the different parameters involved in the present model. The results estimated on the basis of the analytical solutions are presented graphically. The results presented here, show that the flow is appreciably influenced by the presence of slip velocity, couple stress parameter, magnetic field strength as well as the non-uniformity of the channel. This study puts forward an important observation that the occurrence of trapping bolus can be eliminated with suitably adjusting couple stress effect. Moreover, the slip velocity plays a significant role in trapping and transporting food bolus quickly in the digestive system. (C) 2016 Elsevier B.V. All rights reserved.