Effects of the Body Force in the Thermal Lattice Boltzmann Method
Takeshi Seta, Eishun Takegoshi and Kenichi Okui
We show that accuracy of the energy equation is affected by a body force in the Navier-Stokes equation in the thermal lattice Boltzmann model. To remove the harmful effect induced by the body force, we propose a forcing term added to the lattice Boltzmann equation for the internal energy distribution function. The effect of the body force on the energy equation is validated by the natural convection simulation and by numerical experiment where the body force gives sinusoidal wave with various wave numbers. The simulation results demonstrate that not only the compressibility problem but also the gradient of the body force affect the accuracy of the energy equation of the LBM.