Transient Buoyancy- Driven Laminar Convection in an Inclined Three- Dimensional Trapezoidal Enclosure

Abstract

Numerical analysis of transient laminar threedimensional buoyancy-driven convection in an inclined threedimensional trapezoidal air-filled enclosure was investigated in this paper. The right and left sidewalls of the enclosure are kept at constant cold temperatures. The bottom wall is maintained at a constant hot temperature , while the top wall is considered adiabatic. Numerical investigation is performed for Rayleigh numbers varied as 103 ≤ Ra ≤ 105 , while the trapezoidal enclosure inclination angle is varied as 0° ≤  ≤ 180°. Prandtl number is considered constant at Pr = 0.71. Flow and thermal fields are presented in both two and threedimensional pattern. Also, both local and average Nusselt numbers are calculated and discussed. The results show that when the Rayleigh number increases, the flow patterns are changed especially in three-dimensional results and the flow circulation increases. The minimum average Nusselt number inside the trapezoidal cavity corresponds to the highest inclination angle [i.e., 180 ].While, the average Nusselt number reaches its maximum value at    30 . Moreover, when the Rayleigh number increases the average Nusselt number increases as expected.