Numerical computation of unsteady laminar three-dimensional natural convection and
entropy generation in an inclined cubical trapezoidal air-filled cavity is performed for the first time
in this work. The vertical right and left sidewalls of the cavity are maintained at constant cold temperatures.
The lower wall is subjected to a constant hot temperature, while the upper one is considered
insulated. Computations are performed for Rayleigh numbers varied as 103 6 Ra 6 105, while
the trapezoidal cavity inclination angle is varied as 0
6 U 6 180
. Prandtl number is considered
constant at Pr= 0.71. Second law of thermodynamics is applied to obtain thermodynamic losses
inside the cavity due to both heat transfer and fluid friction irreversibilities. The variation of local
and average Nusselt numbers is presented and discussed, while, streamlines, isotherms and entropy
contours are presented in both two and three-dimensional pattern. The results show that when the
Rayleigh number increases, the flow patterns are changed especially in three-dimensional results
and the flow circulation increases. Also, the inclination angle effect on the total entropy generation
becomes insignificant when the Rayleigh number is low. Moreover, when the Rayleigh number
increases the average Nusselt number increases.