Time-dependent hydromagnetic free convection nanofluid flows within a wavy trapezoidal enclosure

This paper considers unsteady MHD free convection flows of alumina (Al2O3)-water and single-walled carbon nanotube (SWCNT)-water nanofluids within a symmetrical wavy trapezoidal enclosure. Initially, the fluid within the enclosure has a constant cold temperature and is at rest. The temperature of the wavy bottom wall is suddenly raised to a constant hot temperature, while the top wall is thermally insulated. The temperature of the side walls is maintained at the initial cold temperature. The dimensionless governing equations with the corresponding initial and boundary conditions are solved using the mixed finite element method with polynomial pressure projection stabilization. The effects of Rayleigh number Ra and Hartmann number Ha on the nanofluid flow and heat transfer are investigated.