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

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U/V 0
0.2
0
-0.2
0 0.2 0.4 0.6 0.8 1
Z
EXP
Y=0.1
U/V 0
0.2
0
-0.2
Y=0.5
0 0.2 0.4 0.6 0.8 1
Z
EXP
U/V 0
0 0.2 0.4 0.6 0.8 1
Figure 6.10 – Wall-normal velocity profiles in the15 ◦ unstable cavity along the
spanwise direction where X=0.5, to illustrate the three-dimensionality of the
flow, Cooper et al. [8]
6.3 Overview of 2-dimensional flow in the tall, dif-
ferentially heated cavities at different angles of
inclination
Figures 6.11-6.19 show the streamlines and temperature contours within
inclined tall cavities, with different angles of inclination in stable or unsta-
ble configurations. The figures show that when the cavity is horizontal and
stable, at 0 ◦ , the flow is stagnant throughout the cavity. When the cavity is in-
clined at 5 ◦ stable configuration, due to density variation along the horizontal
direction, the imbalance between the hydrostatic pressure force and the grav-
itational force generates fluid motion, parallel to the thermally active walls
of the cavity. This in turn creates circulation inside the cavity. As this angle
of inclination increases towards the vertical, the component of gravitational
acceleration parallel to the tall wall increases. This gives rise to stronger circu-
lations.
When the cavity is inclined at the10 ◦ unstable angle, the hot wall is located
below the cold wall. This means that hot fluid with lower density is located
below the cold fluid with higher density. The buoyancy force moves the hot
fluid upwards and cold fluid downwards. As it is shown in the figures, there
are multiple circulation cells inside the 10 ◦ , 5 ◦ and 0 ◦ unstable cavities due to
unstable thermal stratification.
0.2
0
-0.2
Y=0.9
Z
EXP