Comparison of natural convection around a circular cylinder with a square cylinder inside a square enclosure

Numerical calculations are carried out for natural convection induced by a temperature difference between a cold outer square enclosure and a hot inner cylinder with two different geometries (i.e. circular and square). A two-dimensional solution for natural convection is obtained, using the finite volume method for different Rayleigh numbers varying over the range of (1000–100000). The study goes further to investigate the effect of the inner cylinder location on the heat transfer and fluid flow. The location of the inner cylinder is changed vertically along the center-line of square enclosure. The number, size and formation of the cell strongly depend on the Rayleigh number and the position of the inner cylinder. As the obtained total surfaces-averaged Nusselt numbers of the enclosure show, in all cases, at the same Rayleigh number, the rate of heat transfer from the enclosure which the circular cylinder is located inside it is better.

Keywords:

Natural convection , square enclousre , inner circular and square cylinder , different vertical locations , finite volume method