Page 135 - Process Modelling and Simulation With Finite Element Methods

122 Process Modelling and Simulation with Finite Element Methods

1-
3 281
09 - 3 117
2 953
oa- 2 789
2 625
07 - 2 461
2 297
0.6 - 2 133
1 969
I a05
05-
1641
1 477
04 - 1312
1 148
03 - o 9843
0 8203
02- 0 6562
0 4921
01 - 0 3281
0 164
0’
0 0.2 0.4 0.6 0.8
Figure 3.6 Sreamlines for water density model with Gr=lOOOOO.

Figure 3.7 Nusselt number vs. Gravity group Gr”3 for the differential heating of water.
Figure 3.7 shows the high insensitivity of the Nusselt number to gravity group,
i.e. large cavities are required before convective effects dominate. Note that the
scaling of Gr”3 at high Gr was guessed on the grounds of heat flux scaling with
the linear separation of the walls, L, which appears cubed in Gr. At large Gr, the
near linear dependency suggests this asymptotic scaling, until the convective
shearing becomes strong enough that the laminar flow breaks down.