Numerical Study of Slip Effects on Unsteady Asymmetric Bioconvective Nanofluid Flow in a Porous Microchannel With an Expanding/Contracting Upper Wall Using Buongiorno’s Model

Abstract

In this paper, the unsteady fully developed forced convective flow of viscous incompressible biofluid that contains both nanoparticles and gyrotactic microorganisms in a horizontal micro-channel is studied. Buongiorno’s model is employed. The upper channel wall is either expanding or contracting and permeable and the lower wall is static and impermeable. The plate separation is therefore a function of time. Velocity, temperature, nanoparticle species (mass) and motile microorganism slip effects are taken into account at the upper wall. By using the appropriate similarity transformation for the velocity, temperature, nanoparticle volume fraction and motile microorganism density, the governing partial differential conservation equations are reduced to a set of similarity ordinary differential equations. These equations under prescribed boundary conditions are solved numerically using the Runge–Kutta–Fehlberg fourth-fifth-order numerical quadrature in the MAPLE symbolic software. Excellent agreement between the present computations and solutions available in the literature (for special cases) is achieved. The key thermofluid parameters emerging are identified as Reynolds number, wall expansion ratio, Prandtl number, Brownian motion parameter, thermophoresis parameter, Lewis number, bioconvection Lewis number and bioconvection Péclet number. The influence of all these parameters on flow velocity, temperature, nanoparticle volume fraction (concentration) and motile microorganism density function is elaborated. Furthermore, graphical solutions are included for skin friction, wall heat transfer rate, nanoparticle mass transfer rate and microorganism transfer rate. Increasing expansion ratio is observed to enhance temperatures and motile microorganism density. Both nanoparticle volume fraction and microorganism increases with an increase in momentum slip. The dimensionless temperature and microorganism increases as wall expansion increases. Applications of the study arise in advanced nanomechanical bioconvection energy conversion devices, bio-nano-coolant deployment systems, etc.

Stagnation point flow of Maxwell nanofluid containing gyrotactic micro‐organism impinging obliquely on a convective surface

“…Raees et al 30 have discussed the unsteady motion of a bioconvective nanofluid in a channel with a contracting or expanding upper wall. Beg et al 31 studied the transport of a viscous incompressible biofluid containing both nanoparticles and gyrostatic microorganisms in a vertical microchannel with upper wall contracting/expanding. Stefan blowing effects on electrically conducting bioconvection flow of a nanofluid in the presence of motile microorganisms with active and passive nanoparticle flux is analyzed by Giri et al 32 over a stretching sheet.…”

Numerical study of heat transfer and viscous flow in a dual rotating extendable disk system with a non‐Fourier heat flux model

“…The current simulations have considered a no-slip hydrodynamic wall condition for velocity. Future studies will investigate both isotropic and anisotropic hydrodynamic slip 30,37,39,41 and furthermore will also address non-Fourier heat transfer in non-Newtonian fluids, for example, viscoelastic fluids, 65 which are of great relevance to rotating disk bioreactor flows in chemical engineering since such systems feature complex fluids. Additionally the current study could be extended to consider variable thickness of the disk, 66 chemical reactions, 67 and magnetohydrodynamics when the working fluids are electrically conducting.…”

MHD boundary layer bionanoconvective non‐Newtonian flow past a needle with Stefan blowing

“…The nonlinear set of ordinary differential equations, Equations (11)(12)(13)(14) with boundary conditions (15)- (16) are solved numerically in this study by using the BVP4C numerical method in MATLAB for various values of the flow controlling parameters. This method was used by many researchers to solve various complex transport problems.…”

“…The MATLAB bvp4c solver was used for the computation. Bég et al studied the effects of both the expanding and contracting sheet in bioconvection nanofluid dynamics in a deformable channel as a model of a fuel cell. In recent years, many researchers have investigated bioconvection in nanofluids …”