Numerical two-dimensional natural convection in an air filled square enclosure, tilted (25° and 65°) in relation to the horizontal plane, heated from two opposite sides for rayleigh numbers ranging between 10³ and 2.10⁶

Abstract

Steady and transient laminar two-dimensional natural convection of a Newtonian fluid in an inclined square enclosure was numerically investigated. The enclosure was heated on the opposite sides while it was cooled on the other two sides. The inclined angles were 25° and 65° to the horizontal plane. The effect of Rayleigh numbers ranging between 103 and 2.106 on the flow development and heat transfer was studied. It was found that Nusselt number increases with the increase of Rayleigh number. Under low Rayleigh numbers the numerical studies predict the onset of stationary bicellular flow. The study showed that when the Rayleigh number was increased, an overcritical Hopf bifurcation transformed the fixed point to a limit cycle and the steady-state flow becoming oscillatory

KEYWORDS: Natural Convection, Closed Enclosure, Bifurcations, Limit Point, Limit Cycle, Tilt Angle.