HEAT TRANSFER AND 'TURRIJLEhT MIXING LAYERS
105
to determine T; = ATT - ATT which has been done directly with a special
electronic circuit (?; , , , ) and indirectly by measuring
__ - -. - - - - - -
TI2 = (Tr - ATP
from which one obtains the desired value of TF using the relation
T;2 = AT^--^ + F =
where the bracketed term was evaluated from Fig. 15. The result is presented
in Fig. 16 showing a remarkably flat and homogeneous distribution.
I
- 0.2
- 0.1
a1
az
9
0
FIG. 16. Temperature fluctuation variance in the turbulent regime.
8. SUMMARY AND DISCUSSION
The reported observations may be summarized as follows:
(a) From the shape of the temperature fluctuations as well as from the
mean quantity distributions it can be assumed that the transport mechanism
is largely due to a large scale vortical motion (see also Brown and Roshko,
1971).
(b) The mean temperature distribution in the turbulent domain is largely
homogeneous.
(c) The temperature across a single vortex is linear in the mean.
(d) The temperature fluctuation variance in the turbulent domain is approximately constant.