Swirling Flow in a Permeable Tube at Slowly Expanding and Contracting Wall

The swirling flow inside a circular elastic tube with expanding and contracting permeable wall in the presence of a uniform magnetic field is studied analytically. The tube is also assumed to be rotating around its axis with an angular velocity. The governing equations for this multidimensional flow are reduced to nonlinear differential equations with similarity transformations. An analytic series solution is obtained by homotopy analysis method (HAM). The effects of physical parameters on various flow characteristics, such as the velocity, skin friction, and pressure variation, have been analysed briefly. The impact of surface expansion/contraction and rotation has been investigated on the internal boundary-layer flow inside the tube of uniform cross-section.