Computational study of unsteady couple stress magnetic nanofluid flow from a stretching sheet with Ohmic dissipation

Abstract

To provide a deeper insight of the transport phenomena inherent to the manufacturing of magnetic nano-polymer materials, in the present work a mathematical model is developed for time-dependent hydromagnetic rheological nano-polymer boundary layer flow and heat transfer over a stretching sheet in the presence of a transverse static magnetic field. Joule heating (Ohmic dissipation) and viscous heating effects are included since these phenomena arise frequently in magnetic materials processing. Stokes’ couple stress model is deployed to simulate non-Newtonian microstructural characteristics. The Tiwari–Das nanoscale model is adopted which permits different nanoparticles to be simulated (in this article, both copper–water and aluminium oxide–water nanofluids are considered). Similarity transformations are utilized to convert the governing partial differential conservation equations into a system of coupled, non-linear ordinary differential equations with appropriate wall and free stream boundary conditions. The shooting technique is used to solve the reduced non-linear coupled ordinary differential boundary value problem via MATLAB symbolic software. Validation with published results from the literature is included for the special cases of non-dissipative and Newtonian nanofluid flows. Fluid velocity and temperature profiles for both copper and aluminium oxide (Al2O3) nanofluids are observed to be enhanced with greater non-Newtonian couple stress parameter and magnetic parameter, whereas the opposite trend is computed with greater values of unsteadiness parameter. The boundary layer flow is accelerated with increasing buoyancy parameter, elastic sheet stretching parameter and convection parameter. Temperatures are generally increased with greater couple stress rheological parameter and are consistently higher for the aluminium oxide nanoparticle case. Temperatures are also boosted with magnetic parameter and exhibit an overshoot near the wall when magnetic parameter exceeds unity (magnetic force exceeds viscous force). A decrease in temperatures is induced with increasing sheet stretching parameter. Increasing Eckert number elevates temperatures considerably. With greater nanoparticle volume fraction, both skin friction and Nusselt number are elevated, and copper nanoparticles achieve higher magnitudes than aluminium oxide.

Differential transform solution for Hall and ion‐slip effects on radiative‐convective Casson flow from a stretching sheet with convective heating

“…Gupta et al used a variational finite element code to analyze the magnetic micropolar stretching sheet thermal convection flow in the vicinity of a stagnation point. Kumar et al used MATLAB routines to simulate transient magnetic non‐Newtonian nanofluid convective heat transfer from an extending sheet with Joule heating and Stokes couple‐stress rheological model. Vasu et al used homotopy and generalized differential quadrature (GDQ) methods to study magnetized bioconvection of a viscoplastic (Casson) fluid from a stretching surface.…”

A comparative analysis of multiple fractional solutions of generalized Couette flow of couple stress fluid in a channel

“…The CSF model has been considered by Akgül and Siddique 2 in this study they discussed the novel applications of CSF flows between two parallel plates. The applications of MHD CSF flow between two parallel plates were investigated by Siddique et al 3 Kumar et al 4 also discussed unsteady couple stress nanofluid flow with Ohmic dissipation. Khan et al 5 analyzed the swirling of a CSF using a rotating disk.…”

Analysis of MHD Fluids around a Linearly Stretching Sheet in Porous Media with Thermophoresis, Radiation, and Chemical Reaction

“…e purpose of the current study is to discuss the comparative impact of MHD flow [27][28][29][30] of Newtonian, Maxwell, Williamson, and Casson fluids under the effects of internal heat source/sink, thermal radiation, chemical reaction, and thermophoretic velocity [31][32][33][34][35][36] on the momentum and heat and mass transfer over a stretching sheet with permeability effects [37][38][39][40][41].…”