Instability at the onset of natural convection

Magherbi

Dear sir, I undertake a numerical study using VCEF method in the goal to determinate entropy generation (Entropy generation is proportional to (Grad(T)**2))at the onset of naturel convection for a Newtonien incompressible fluid enclosed in a differentiel heated square cavity( submitted to an horizontal thermal gradient, the horizontal walls are adiabatic). It is found that for small Rayleigh number total entropy generation increases to reach a maximum , then deceases asymptotically toward a constant value in the steady state. for higher Rayleigh number total entropy generation increases and reach its maximum, but it deacreases with an oscillatory regime before reaching the steady state. other thermodynamics

Best regards

Mag