A novel two-dimensional coupled lattice Boltzmann model for thermal incompressible flows

摘要

A novel two-dimensional coupled lattice Boltzmann model is developed for thermal incompressible fluid flows. A modified equilibrium distribution function is proposed in the present model. A mesoscopic discrete force is coupled into the modified equilibrium distribution function based on the Boussinesq approximation. The outstanding advantages of the standard lattice Boltzmann method are retained in present model besides better numerical stability. The present model is validated by the numerical simulation of the natural and Rayleigh–Benard convection at a wide range of Rayleigh numbers. Excellent agreement between the present results and previous lattice Boltzmann method or theoretical prediction demonstrates that present model is an efficient numerical method for natural and Rayleigh–Bénard convection. Further, present model is also successfully assessed considering Rayleigh–Taylor instability. It is also easier and convenient to be implemented as compared with the previous thermal models.