Unsteady flow of nanofluids past a vertical flat plate with leading edge accretion or ablation

Unsteady flow of a nanofluid past a semi-infinite vertical flat plate is theoretically investigated. Unsteadiness is caused by steady rates of accretion or ablation at leading edge. Two types of nanofluids, namely, Cu-water and Ag-water are considered, with Prandtl number Pr = 6.2. Governing partial differential equations are transformed into ordinary differential equations, using a similarity transformation. The resulting ordinary differential equations are solved numerically. Results are compared with those of regular fluid (ϕ = 0) with Pr = 0.7 and comparison shows good agreement with previous results. Effects of nanoparticle volume fraction on flow and heat transfer characteristics, influence of buoyancy force and unsteady parameter, are presented and discussed in detail. It is found that effects of the volume fraction on skin friction and wall temperature gradient are more significantly influential in Ag-water solution than in Cu-water solution. (author)