Unsteady axisymmetric radiative Cu-Al2O3/H2O flow over a radially stretching/shrinking surface

The unsteady stagnation point flow of hybrid nanofluid past an impermeable disk is investigated with the presence of thermal radiation. The pair of aluminium oxide and copper with 2% of phi hnf are numerically analyzed using the existing correlations of hybrid nanofluid. The governing model is simplified into a set of differential (similarity) equations and then, numerically solved by employing the bvp4c solver in the Matlab software. The dual solutions are presented while the stability analysis certifies the physical/real solution. The availability of dual solutions is detected when the range of control parameters are -1.5 <= B <= -1 (unsteadiness decelerating parameter), 0 <= R <= 0.1 (radiation parameter) and lambda c <= lambda <= 0.5 (velocity ratio parameter). The accession of radiation parameter and the use of different nanofluids (Cu-H2O, Al2O3-H2O and Cu-Al2O3/H2O) are not prolonging the boundary layer separation. However, the addition of R, B and the use of Cu-Al2O3/H2O hybrid nanofluid enhance the thermal performance of the working fluid.

Automated summary

This study investigates the unsteady stagnation point flow of a hybrid nanofluid past an impermeable disk in the presence of thermal radiation. The numerical analysis is conducted on a pair of aluminium oxide and copper with 2% of phi hnf using existing correlations of hybrid nanofluid. The governing model is simplified into a set of differential equations and solved numerically. The results show the presence of dual solutions and the enhancement of thermal performance when adding the radiation parameter and using Cu-Al2O3/H2O hybrid nanofluid.