Effects of a magnetic field on trapping through peristaltic motion for generalized Newtonian fluid in channel

We investigate the effects of magnetic field on trapping at the centerline and at the channel wall for Carreau fluid through uniform channel. The problem is formulated using a perturbation method (to second order) in terms of Weissenberg number (Wi). It has been noted that the pressure rise and friction force for Newtonian and Carreau fluids increase with Hartmann number M except at certain values of volume flow rate. The trapping limit and the trapping occurrence region at the centerline increase with M but they are independent approximately of M at certain values of amplitude ratio. Furthermore, the trapping occurrence region (at the wall) decreases as M is increased. Also, the magnitude of vertical velocity and shearing extra stress increase with M in contraction region. The peristaltic pumping and the augmented pumping are discussed for various values of the physical parameters of interest. (c) 2005 Elsevier B.V. All rights reserved.