Eur. Phys. J. Plus (2019) 134: 144
https://doi.org/10.1140/epjp/i2019-12481-9

Regular Article

Pulsatile flow and heat transfer of shear-thinning power-law fluids over a confined semi-circular cylinder

Department of Chemical Engineering, Indian Institute of Technology Roorkee, 247667, Roorkee, India

^* e-mail: amitdfch@iitr.ac.in

Received: 19 February 2018
Accepted: 17 December 2018
Published online: 12 April 2019

Abstract

This work is an attempt to simulate the effects of pulsating flow upon the thermal and hydrodynamic behavior of shear-thinning non-Newtonian fluid (approximated as power-law fluid) while it flows past a semi-circular cylinder fixed in a symmetrically confining channel and deduces the optimum oscillating frequencies and amplitude for a particular power-law index (n) and Reynolds number (Re). The semi-circular cylinder studied has a fixed temperature while the wall confinement is insulating. The ranges of control parameters varied are -100 (based on object's diameter), the amplitude of oscillation (A) = 0-0.6, the Strouhal number (St) = 0-2 and the n ranging from 0.2 to 1. The Prandtl number has been kept fixed at (which corresponds to several fluids of industrial importance like n-butanol, etc.). The isotherms and streamlines give a qualitative insight into the heat and flow transfer behavior as various parameters are varied, while the Nusselt number, overall drag and lift coefficients have been calculated to get a quantitative insight. Further, the augmentation in heat transfer and the decline in drag upon using a pulsating non-Newtonian fluid inlet as opposed to using a steady Newtonian flow have been established. Lastly, the temporal variations and the frequency of vortex shedding have been studied using a fast Fourier transform.