The computation of turbulent natural convection flows - Turbulence ...

Numerical Implementation 132
The matrix coefficient that links the near wall node and the wall is set to zero.
Regarding the non-wall boundary condition, three types of boundary con-
ditions are employed in the study. Two of them are inlet and outlet boundaries
across which the fluid is entrained into the computational domain and exits it
respectively. The other boundaries employed in the present work are treated
as symmetry boundaries. At this type of boundary, the fluid neither enters to
the domain nor exits.
A fixed constant temperature is set for the inlet boundary condition and
zero gradient condition is imposed for the rest of the variables. Zero gradient
conditions are also set for all variables at the outlet of the computational do-
main. For the symmetry boundaries, the component of velocity perpendicular
to the boundary is set to zero and zero gradient conditions are imposed to the
rest of the variables.
5.8 Simulation of inclined cavity
The most expedient way to simulate inclined cavity flows was to rotate the
coordinate system and consequently the velocity components relative to the
vertical, as shown in Figure 5.4. This means that the gravity vector now has
components in both the x and y directions.
x
y
ψ
H
Hot Wall
g y
g
g x
Cold Wall
Figure 5.4 – Schematic of the inclined cavity.
The components of gravity acceleration are:
L