A Comparative Solution of Natural Convection in an Open Cavity using Different Boundary Conditions via Lattice Boltzmann Method

A Lattice Boltzmann method is applied to demonstrate the comparison results of simulating natural convection in an open end cavity using different hydrodynamic and thermal boundary conditions. The Prandtl number in the present simulation is 0.71, Rayleigh numbers are 104,105 and 106 and viscosities are selected 0.02 and 0.05. On-Grid bounce-back method with first-order accuracy and non-slip method with second-order accuracy are employed for implementation of hydrodynamic boundary conditions. Moreover, two different thermal boundary conditions (with first and second order of accuracy) are also presented for thermal modelling. The results showed that first and second order boundary conditions (thermal/hydrodynamic) are the same for a two-dimensional, single phase, convective heat transfer problem including geometry with straight walls. The obtained results for different hydrodynamic and thermal boundary conditions are useful for the researchers in the field of lattice Boltzmann method in order to implement accurate condition on the boundaries, in different physics.