MHD couple stress boundary-layer flow with heat and mass transfer under thermal radiation and Marangoni effect: A numerical study

This research deals with the investigation of radiative boundary-layer flow of couple stress nanofluids under the Marangoni effect in terms of heat and mass transfer. The approach also takes into account the effects of cross diffusion and magnetic field. Additionally, the study of the nanoparticle interfacial layer features under an appropriate nanofluid model has been performed. Using similarity transformation, the mathematical issue is transformed to ordinary differential equations, that are then numerically resolved applying MATLAB solver bvp5c. Utilizing the Response Surface Methodology, the face-centered Central Composite Design is used as the foundation for the optimization process. The flow fields with nanolayer and without it are compared. For interacting effects, the system external constraining factors, such as the couple stress parameter, magnetic field, thermal radiation, Dufour, Schmidt and Soret numbers has been investigated. The heat and mass transfer sensitivity is closely examined. Through graphical representations, the flow fields embedded dimensionless parameters are investigated. The interfacial layer aspect leads to an enhanced magnitude of the temperature field whereas the effect on the concentration profile is negligible. The inclination of the magnetic field augments the flow profiles significantly. Further, the velocity increases near the boundary and then reverses its direction at the free stream for increment in the couple stress characteristic. The temperature and concentration are enhanced for large values of couple stress parameter.