Abstract
Flow in converging/diverging channels under the influence of external magnetic field is presented. The walls of the channels are taken to be stretching/shrinking. Buongiorno's model is used to formulate the problem for nanofluids. It is to be highlighted that such models arise frequently in biosciences. The equations governing the flow are transformed to a set of nonlinear ordinary differential equations by employing appropriate similarity transformations. Two efficient techniques variational iteration method (VIM) and variation of parameters method (VPM) are employed to tackle the complexity and nonlinearity of the presented model. Comprehensive discussions on the results obtained are provided. Comparison of the obtained results with existing literature re-confirms the credibility of solution obtained via VIM and VPM.