Numerical simulation of unsteady natural convection from heated horizontal circular cylinders in a square enclosure

In this article, a 2-D numerical study is carried out to investigate the effect of this interaction on natural convection from two heated horizontal cylinders confined in a square enclosure with isothermal walls at the heat sink temperature. The simulations are carried out for Rayleigh numbers between 10³ and 10⁷, and dimensionless horizontal distances of cylinders between 0.1 and 0.4. The results show that the variation of the area-averaged Nusselt number strongly depends on the distance between the two cylinders if Rayleigh numbers are less than 10⁴. In contrary, the effect of cylinder spacing on heat transfer was found to be nearly negligible when the Rayleigh number is between 10⁴ and 10⁷. It is also observed that steady state flow and heat transfer undergo periodical oscillation, and ultimately chaotic oscillation in special positions of cylinders can occur.