Transportation of activation energy in the Oldroyd-B nanofluid by considering double stratification over a surface with variable thickness

Abstract

In this communication, the impact of activation energy on the nonlinear binary chemically reactive flow of an Oldroyd-B nanofluid has been examined. Buongiorno’s nanofluid model is used in mathematical modelling. The flow behaviour is discussed over a nonlinear stretchable surface with variable thickness. Nonlinear mixed convection is considered. The energy equation is modelled subject to a heat source / sink and radiative flux. Furthermore, double stratification at the boundary of the sheet is considered for the heat and mass transfers. Important slip mechanisms such as Brownian and thermophoresis diffusions are accounted. The obtained flow expressions are analytically solved by using the optimal homotopy asymptotic method (OHAM). Computational analysis for concentration, temperature and velocity is obtained and discussed using plots. Nusselt and Sherwood numbers are discussed using a tabulated form. Total squared residual error is calculated for velocity, temperature and concentration. The obtained results show that for increased values of Hartmann (magnetic parameter) and Deborah numbers, the fluid velocity decreases. The temperature field shows an increasing impact in the presence of larger radiative parameters. Sherwood and Nusselt numbers increase with higher values of thermophoresis and solutal stratified parameters.