Unsteady micropolar hybrid nanofluid flow past a permeable stretching/shrinking vertical plate

Abstract

The current analysis aims to find the solution to the buoyancy effect on time-dependent flow and heat transfer induced by a hybrid micropolar nanofluid over a permeable shrinking or stretching vertical flat plate. A novel hybrid nanofluid is utilized, which consists of the agglomeration of water (pure fluid) and two dissimilar nanoparticles like silver (Ag) and titanium dioxide (TiO2). Initially, the model is developed in the form of the non-linear partial differential equations (PDEs) with three independent variables, which are transformed to the set of dimensionless ordinary differential equations (ODEs) using the appropriate similarity transformations. These dimensionless ODEs are solved numerically via the bvp4c package in MATLAB software. The consequence of various involved controlling parameters on the velocity, microrotation, friction drag, temperature, and heat transfer characteristics for the upper branch solution (UPBS) and the lower branch solution (LOBS) are thoroughly inspected. In physical engineering quantities of interest, it is deeply observed that for the case of stretching, the solution of the stable (upper) branch is possible for the entire negative and positive selected values of the stretching/shrinking parameter. In contrast, the lower branch solution exists only for negative values of the stretching/shrinking parameter for the shrinking case.