Linear stability analysis of (Cu-Al2O3)/water hybrid nanofluid flow in porous media in presence of hydromagnetic, small suction and injection effects

In this paper, a stability analysis of a hybrid nanofluid flow between two parallel and stationnary plates filled with a porous medium was investigated. The hybrid nanofluid is composed of water as regular fluid, copper (Cu) and alumina (Al2O3) as nanoparticles. A mathematical modeling of the problem was developed by taking account other effects such as aspiration (suction/injection) and magnetic field. An eigenvalue differential equation namely the modified Orr-Sommerfeld equation governing the stability of the flow was derived and solved numerically by spectral collocation method with expansions in Chebyshev polynomials. The effect of the density of particles, suction/ injection Reynolds number, Hartmann number, Darcy number and volume fraction on the flow stability was examined and presented. It was found the following: the Darcy number affects the stability of the flow, the suction/injection reduces the drag and the transition is delayed/prevented, the magnetic field makes the dissipation very important because the kinetic energy of the electrically conductive fluid is absorbed by the Lorentz force, and the volume fraction and the density of nanoparticles increased the inertia of the fluid which decreased the speed gradient and damped the disturbances. (C) 2020 The Authors. Published by Elsevier B.V. on behalf of Faculty of Engineering, Alexandria University.