Impact of gravity-induced and Fourier’s heat flux on the nano-film flow over thermal sensitive surface

Abstract

This article investigates the phenomenon of gravity-driven flow of nanoliquid film along a vertical surface under the effects of nonlinear thermal radiations. The falling nanofluid film is subjected to a convectively heated surface along with slip condition. The flow and thermal properties are investigated considering four different nanoparticles namely Ag (silver), Cu (copper), $$\mathrm {TiO}_2$$ (Titania) and $$\mathrm {Al}_2\mathrm{O}_3$$ (alumina) with water as a acting base fluid. The physical model is presented in terms of nonlinear partial differential equations. These equations are reduced to a system of nonlinear ordinary differential equations through similarity transformations. The problem is solved numerically utilizing Bvp4c function in MATLAB. Multiple solutions are presented for unfavorable buoyancy or opposing flow ( $$\sigma <0$$ ) and favorable buoyancy or assisting flow ( $$\sigma >0$$ ). The impact of nanoparticle volume fraction is found to be useful in intensifying the temperature and dropping heat transfer rate because of dominant convection. It is worth mentioning that silver nanoparticles in the thin film of nanofluid lead to higher wall shear stress and heat transfer rate. The increasing nature of skin friction coefficient $$(C_f)$$ is examined in buoyancy assisting flow while in opposing buoyancy flow its behavior is noticed reduced for various values of solid fraction ( $$\phi $$ ) of $$\mathrm {Ag}$$ nanoparticles.