The effect of buoyancy force on natural convection heat transfer of nanofluid flow in triangular cavity with different barriers.

This article aims to investigate the thermophysical properties of viscous nanofluid in the two-dimensional geometry of a triangular cavity containing inverted triangle, square, and rhombus obstacles with different boundary conditions. The boundary conditions of the triangular cavity are investigated in two mechanisms: 1) uniform temperature at the base of the cavity and 2) non-uniform temperature (sinusoidal function) at the base of the cavity. The finite element method was used to solve the governing equations of the viscous nanofluid flow. The effect of flow control parameters on velocity and temperature profile is considered in a wide range of Rayleigh and Prandtl numbers. The innovation of this study is to use different obstacles in the two-dimensional geometry of the triangular cavity and compare their velocity profiles and temperature distribution in different boundary conditions. The results show that in the obstacles used in the triangular cavity, with the increase of buoyancy force and Rayleigh number, the values of velocities increased and caused the formation of vortex flow, and the pattern of velocity vectors in the cavity with the rule of uniform temperature has given a distinctive feature. Also, the application of trigonometric temperature functions in general and sinusoidal temperature functions in particular with high frequency can effectively create a vortex flow and increase the heat transfer rate.