There are currently only a few theoretical studies on convective heat transfer in polymer nanocomposites. In this paper, the unsteady incompressible flow of a polymer nanocomposite represented by an Oldroyd-B nanofluid along a stretching sheet is investigated. Recent studies have assumed that the nanoparticle fraction can be actively controlled on the boundary, similar to the temperature. However, in practice, such control presents significant challenges and in this study the nanoparticle flux at the boundary surface is assumed to be zero. We have used a relatively novel numerical scheme; the spectral relaxation method to solve the momentum, heat and mass transport equations. The accuracy of the solutions has been determined by benchmarking the results against the quasilinearisation method. We have conducted a parametric study to determine the influence of the fluid parameters on the heat and mass transfer coefficients.

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An unsteady, laminar, mixed convective stagnation point nano uid ow through a permeable stretching at surface using internal heat source or sink and partial slip is investigated. The e ects of thermophoresis and Brownian motion parameters are revised on the traditional model of nano uid for which nano uid particle volume fraction is passively controlled on the boundary. Spectral relaxation method is applied here to solve the nondimensional conservation equations. The results show the illustration of the impact of skin friction coe cient, different physical parameters, and the heat transfer rate. The nano uid motion is enhanced with increase in the value of the internal heat sink or source. On the other hand, the rate of heat transfer on the stretching sheet and the skin friction coe cient are reduced by an increase in internal heat generation. This study further shows that the velocity slip increases with decrease in the rate of heat transfer. The outcome results are benchmarked with previously published results.

We study the unsteady convective flow of two water-based nanofluids containing Copper and Titanium oxide along a vertical stretching or shrinking cone with viscous dissipation and internal heat generation. The problem is transformed to two-dimensional flow over a cone using Mangler's transformation. The coupled nonlinear conservation equations are solved numerically using the spectral local linearization method. We present an analysis of how some physical parameters affect the flow structure, the heat and mass transfer rates and the fluid properties. The accuracy of the results is determined by comparison with previously published studies, for some limiting cases.