Abstract:
A theoretical study is presented for transient peristaltic flow of an incompressible fluid with variable viscosity in a finite
length cylindrical tube as a simulation of transport in physiological vessels and biomimetic peristaltic pumps. The current
axisymmetric analysis is qualitatively similar to two-dimensional analysis but exhibits quantitative variations. The current
analysis is motivated towards further elucidating the physiological migration of gastric suspensions (food bolus) in the
human digestive system. It also applies to variable viscosity industrial fluid (waste) peristaltic pumping systems. First, an
axisymmetric model is analysed in the limit of large wavelength (a ,, l ! 1) and low Reynolds number (Re ! 0) for
axial velocity, radial velocity, pressure, hydromechanical efficiency and stream function in terms of radial vibration of the
wall (h), amplitude of the wave (f), averaged flow rate (Q ) and variable viscosity (mðrÞ). Subsequently, the peristaltic flow
of a fluid with an exponential viscosity model is examined, which is based on the analytical solutions for pressure, wall shear
stress, hydromechanical efficiency and streamline patterns in the finite length tube. The results are found to correlate well
with earlier studies using a constant viscosity formulation. This study reveals some important features in the flow
characteristics including the observation that pressure as well as both number and size of lower trapped bolus increases.
Furthermore, the study indicates that hydromechanical efficiency reduces with increasing magnitude of viscosity parameter.
