Eur. Phys. J. Spec. Top. (2021) 230: 1435-1445
https://doi.org/10.1140/epjs/s11734-021-00053-9

Regular Article

Double-diffusive instability of Casson nanofluids with numerical investigations for blood-based fluid

¹ Dr. S.S. Bhatnagar University Institute of Chemical Engineering and Technology, Panjab University, 160014, Chandigarh, India
² University Institute of Engineering and Technology, Panjab University, 160014, Chandigarh, India
³ Energy Research Centre, Panjab University, 160014, Chandigarh, India

^b jyoti.maths@gmail.com

Received: 26 September 2020
Accepted: 2 February 2021
Published online: 19 April 2021

Abstract

The paper investigates analytically the instability of Casson binary nanofluids and further numerically by taking blood as the base fluid. The blood being a non-Newtonian fluid is characterized by Casson model and is assumed to undergo nano-scale, solutal and buoyancy effects which induce convection currents in the flow. Nanoparticle volume fraction is taken to be so small in the fluid that initially it is assumed to be constant. Small disturbances are added to the solution and normal mode technique is used to convert partial differential equations into ordinary. Further, these equations are solved using one term Galerkin method for free–free, rigid–free and rigid–rigid boundaries. The complex expressions of Rayleigh number are simplified with valid approximations to get analytical results. Thermal, solutal and nano-scale effects are found to contribute equally and independent of each other while their overall impact is inversely proportional to Casson parameter. To get a complete insight of the problem, complex analytical expressions are explored numerically and the effects of various parameters on the instability of blood are depicted graphically using the software Mathematica. The alumina nanoparticles have more destabilizing impact on blood than copper and could play a significant role on human health, more specifically in the cardiovascular system.