Unsteady free convection in a porous open wavy cavity filled with a nanofluid using Buongiorno's mathematical model

A numerical investigation is performed on the unsteady free convection heat transfer characteristics of a nanofluid confined within a porous open wavy cavity using the mathematical nanofluid model proposed by Buongiomo. In modeling the cavity, it is assumed that the left wall has a wavy surface, while the right wall is flat. In addition, it is assumed that the two vertical walls of the cavity are impermeable and isothermal, while the bottom wall is adiabatic. In performing the analysis, the governing equations are modeled using the Boussinesq approximation and are solved numerically using the finite-difference method with the second-order differencing schemes. The simulations focus on the respective effects of the undulations number, shape coefficient, and dimensionless time. Particular efforts have been focused on the effects of these parameters on the fluid flow, heat, and mass transfer characteristics. The results show that the average Nusselt and Sherwood numbers decrease with an increase in the undulations number. At the same time, the average Nusselt and Sherwood numbers can be optimized via an appropriate tuning of the wavy surface geometry parameters. (C) 2015 Elsevier Ltd. All rights reserved.