HEAT TRANSFER A N D TURJSVLENT MIXING LAYERS
97
FIG. 3. sdf-prcscrving r e g h and virtual origin.
The measurements which follow herein were restricted to the selfpreserving region and plotted versus the mn dhtnmsiond coordinate
tt = Y / ( X - x*).
5. THE DISTRIBUTION OF MEAN VELOCITY A N D OF MEAN TEMPERATURE
The distribution of the mean velocity was measured lor ATo = 0 and
AT, = 26°C. For the cold flow tbe spread poraff#kb was e = 11. In the
heated flow case the spread, especially in thc Outcc @e., low velocity) region
of the shear layer is somewhat larger. The h W distribution of the m a n
temperature, shown in Fig. 4, exhibits a strikingIy di&rent character when
compared with the maan velocity. Aa a n be we@ trOm Fig. 5, the d o c i t y
distribution curve has a singk inflexion point indiqthg an ordinary gradient diffusion mechanism for the momentum. In contrast to this the mean
'temperature distribution curve has three infkxion points (S-shape) with a
somewhat flat region at large values of y. This peculiar shape of the curve
suggests a transport mechanism largely deterrtlined by quasi convective
action due to large scale vortex m h n (bulk mwction).