hi, i am using natural convection in simulating quenching of hot cylinder in oil.i have four question. 1.how you determine value of g in operating condition and what its effect. 2.when you use this model how density in material properties is determined or simply density is given at that temperaure in data tables. 3.what will be operating temerature if fluid is at 313 and cylinder wall will be at 1473K. 4.for transient you use first steady and then unsteady.Can i use coupled in steady and segregate in transient.how can i determine which solver i should use. nabeel

In the Boussinesq model, the fluid density is assumed to be the same except it appears in the N-S equation with the graviation g as a bouyancy term. So the oil density inside the cylinder will not change. Maybe you should not use the Boussinesq model?