Mixed convection in gravity-driven nano-liquid film containing both nanoparticles and gyrotactic microorganisms

Abstract

Analysis of a gravity-induced film flow of a fluid containing both nanoparticles and gyrotactic microorganisms along a convectively heated vertical surface is presented. The Buongiorno model is applied. Two kinds of boundary conditions, the passive and the active boundary conditions, are considered to investigate this film flow phenomenon. Through a set of similarity variables, the ordinary differential equations that describe the conservation of the momentum, the thermal energy, the nanoparticles, and the microorganisms are derived and then solved numerically by an efficient finite difference technique. The effects of various physical parameters on the profiles of momentum, thermal energy, nanoparticles, microorganisms, local skin friction, local Nusselt number, local wall mass flux, and local wall motile microorganisms flux are investigated. It is expected that the passively controlled nanofluid model can be much more easily achieved and applied in real circumstances than the actively controlled model.

Thermophoresis and Brownian motion effects on MHD bioconvection of nanofluid with nonlinear thermal radiation and quartic chemical reaction past an upper horizontal surface of a paraboloid of revolution

“…In this study, it is also assumed that the existence of spherical nanoparticles has few effects on the motion of the microorganisms. Following the idea and mathematical formulation stated in Kuznetsov and Nield [36], Kuznetsov and Nield [37] and Raees et al [30] the flux of microorganisms through the boundaries is equal to zero. Mathematically, this can be expressed as…”

“…Sandeep et al [29] reported stagnation point flow, heat and mass transfer behavior of MHD Jeffrey nanofluid in the absence of bioconvection. Recently, Raees et al [30] reported that bioconvection in nanofluids has great potential in Colibri microvolumes spectrometer and also to improve the stability of nanofluids.…”

Stability Analysis of MHD Stagnation-point Flow towards a Permeable Stretching/Shrinking Sheet in a Nanofluid with Chemical Reactions Effect

“…It is assumed that the velocity of the stretching/shrinking sheet is u w (x) = ax, where a > 0 corresponds to the stretching sheet and a < 0 is for the shrinking case, while the free stream velocity is u e (x) = bx, where b is a positive constant. Under these assumptions, the governing equations can be written as (Bachok et al 2013;Othman et al 2017;Raees et al 2015):…”

Thermal diffusion and diffusion thermo effects of Eyring‐Powell nanofluid flow with gyrotactic microorganisms through the boundary layer

“…Tausif et al studied the multiple slip effects on bioconvection of nanofluid flow containing gyrotactic microorganisms and nanoparticles. Raees et al studied mixed convection in the gravity‐driven film flow of a fluid containing both nanoparticles and gyrotactic microorganisms. Magnetic field analysis in a suspension of gyrotactic microorganisms and nanoparticles over a stretching surface was presented by Noreen et al The main purpose of this paper is to extend the work of Mohyud‐Din et al to include the non‐Newtonian Eyring‐Powell model, ohmic dissipation, viscous dissipation, and chemical reaction.…”