Modeling and analysis of the triple diffusion unsteady flow of couple stress nanofluid with variable viscosity and distinct thermal sources

Thanks to their optimal thermal characteristics, nanomaterials stand out for their varied applications in heat transfer systems, energy storage, industrial processes, and biomedical research. Recently, scientists explored various dynamic properties in nanofluid flow to develop an even better thermal model. In this context, the phenomenon of triple diffusion in nanofluids constitutes an active area of research, offering promising applications in nanotechnology, metallurgical processes, chemical reactors, and thermo-diffusion processes. This paper analyzes the triple diffusion flow of a torque-constrained nanofluid, induced by a periodically oscillating porous surface, taking into account the importance of variations in thermal consequences. The viscosity of the torque-constrained nanofluid is assumed to be temperature-dependent. The analysis takes into account the variable role of thermal conductivity, mass diffusivity, and solute volume fraction. The modeling of the problem is expressed by coupled nonlinear partial differential equations. The semi-analytic technique, known as the homotopic analysis scheme, is used for resolution. The solution is validated and confirms the convergence region. The physical aspects of the parameters are examined with regard to the parameters involved. The simulated observations reveal that with the Dufour–Lewis factor and varying mass diffusivity, an increase in solute concentration is seen. The concentration of nanoparticles decreases with the nano-Lewis number.