Entropy generation in local non-similar dissipative MHD flow of CH3OH + Fe3O4 and C12H26-C15H32 + Fe3O4 ferrofluids

•This analysis examines the local non-similar flow of two nanofluids with base fluids (methanol and kerosene oil) containing magnetite nanoparticles.•Governing boundary layer equations do not admit the similarity solutions in presence of mixed convection.•The local non-similarity approach is implemented, and solutions are obtained by using the two-equation model.•Comparison between heat transfer characteristics is performed by incorporating viscous and ohmic heating.•The slope linear regression (SLR) technique is used to calculate the rate of decrease/increase in shear stress as well as the rate of heat transfer at the boundary. This analysis examines the local non-similar flow of two nanofluids with base fluids (methanol and kerosene oil) containing magnetite nanoparticles. Comparison between heat transfer characteristics is performed by incorporating viscous and ohmic heating. The flow is induced by a linear vertically stretching surface, and corresponding governing boundary layer equations do not admit the similarity solutions because the mixed convection parameter is not free from the streamwise coordinate. Therefore, the local non-similarity approach is implemented, and solutions are obtained by using the two-equation model. Graphs are displayed to investigate the impacts of dimensionless parameters on velocity profile, temperature distribution, entropy generation and the Bejan number. The linear regression model is applied to investigate the rate of growth/decrease of the skin friction coefficient and Nusselt's number with growing values of physical parameters. Values of the skin-friction coefficient and Nusselt’s number are also obtained from the first level of truncation (one-equation model) and the second level of truncation (two-equation model). Comparative analysis reveals that relative error between the numerical values obtained from the first and second levels of truncation is an increasing function of the transformed streamwise coordinate.