Abstract
This paper studies effect of the time and space fractional derivatives orders on the unsteady fluid flow and heat transfer inside a square enclosure filled with Cu-H2O nanofluid. An active part is located in the bottom wall of the enclosure and theory of the conformable fractional derivatives is applied on the time and space derivatives. The governing fractional partial differential equations are solved numerically using the finite difference method and the obtained results are presented in terms of the streamlines, isotherms, velocity component, local and average Nusselt numbers. The results revealed that the local and average Nusselt numbers are enhanced as either the time fractional derivatives order or the space fractional derivatives order decreases. Also, effects of variations of the time fractional derivatives order are significant only at the low values of the time parameter.