  A theoretical analysis is carried out to study flow evolution inside the
laminar Rayleigh-B\'enard convection system laden with small particles. By
describing particle dynamics and particle heat as sources of drag and heat
respectively, the physics of particle impact on the flow evolution is studied.
It is found that due to the relative velocity of the particulate phase to the
fluid phase, particles work as a superimposed moment on the whole flow,
attenuating the flow intensity. When the relative temperature of the
particulate phase to the fluid phase occurs, particles act like a superimposed
moment of buoyancy force on the whole flow, causing alterations in both flow
intensity and flow direction.
