The significance of coherent flow structures for the turbulent mixing ...

7 Investigation of the yz-plane
7.5.3 Stream-wise vortices
In oder to examine the extent of the stream-wise vortices for different wall distances two pairs
of velocity fields are shown in figure 7.21 and figure 7.22 which where measured simultaneously
in spatially separated planes. The distance between both measurement planes is 325
wall-units. The first pair of velocity fields reveals hairpin like structures at a moderate wall
distance, as indicated by the coloured circles in the top image. However, when the lower image
is considered at the location where the vortices appear in the upper image, it is difficult to
500
400
y
+
300
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100
0
0 100 200 300 400 500 600 700 800
500
y [???]
x [???]
400
300
y
+
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0
0 100 200 300 400 500 600 700 800
z
+
y [???]
x [???] 160
FIGURE 7.22: Same as figure 7.21.