Dynamics of tangent-hyperbolic nanoliquids configured by stratified extending surface: Effects of transpiration, Robin conditions and dual stratifications

Abstract

A mathematical study is presented to evaluate double stratification effects on the dual convected flow of a non-Newtonian (tangent-hyperbolic) nanoliquid persuaded by porous stretching surface. Thermal radiation along with transpiration (wall suction/injection) and heat source/sink are included. Buongiorno's model is employed for nanoscale effects and a Rosseland diffusion approximation for nonlinear radiative heat transfer. Appropriate similarity transformations are deployed to alter the dimensional governing nonlinear PDEs (partial differential equations) to a nonlinear differential one with physically viable boundary conditions. The transformed dimensionless BVP (boundary value problem) is computed analytically by a HAM (homotopic analysis method) algorithm and a symbolic software. Validation with earlier studies employing the numerical method (Runge-Kutta-Fehlberg) is included. The evolution in velocity, thermal and solutal (nanoparticle) fields are interpreted through graphical outcomes for the impact of significant sundry parameters. Tabular outcomes are also presented for skin-friction, local Nusselt and Sherwood numbers. A rise in material variable (Weissenberg number), the flow is decelerated while it is accelerated with increasing nonlinear thermal convective parameter, mixed convection parameter and buoyancy ratio values. Temperatures are boosted with increment in radiative, thermophoresis, Brownian motion, thermal Biot number and heat generation parameters whereas they are reduced with increasing thermal stratification parameter. Nanoparticle concentration values are suppressed with higher Schmidt number, Brownian movement and solutal stratification variable however they are boosted with greater values of thermophoresis and concentration Biot number. Local Sherwood number is improved with Schmidt number, concentration stratification parameter and concentration Biot number. Local Nusselt number is strongly increased with greater Prandtl number, thermal stratification number, thermal Biot number and radiative parameter. The study finds applications in thermal nano-polymeric coating flows in materials processing operations.