Flow over a Magnetically Suspended Cylinder in an Axial Free Stream

80
u/U
65
50
35
20
5
z(mm)
-10
-25
-40
-55
-70
1.00 -1.02
0.98 -1.00
0.96 -0.98
0.94 -0.96
0.92 -0.94
0.90 -0.92
0.88 -0.90
0.86 -0.88
0.84 -0.86
0.82 -0.84
0.80 -0.82
-85
-70
-55
-40
-25
-10
5
20
35
50
65
80
-85
y(mm)
Figure 3 Mean axial velocity (u/U) distribution in the wake of the 45mm diameter cylinder,
L/D=5.02 at x/D= 6.11 (Re D =100,000)
1.05
1.00
0.95
y traverse
y traverse (mirror image)
z traverse (mirror image)
z traverse
u/U
0.90
0.85
0.80
-2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0
y/D or z/D
Figure 4 Mean velocity profiles along 2 axes in the wake
a 45mm diameter L/D=5.02 axial cylinder at x/D= 6.11
The streamwise variation of the mean velocity in the wake was measured behind the 25mm diameter cylinder
with a single hot wire probe, and the results are shown in Fig. 5. When the virtual origin of the wake was taken to be
1.3D downstream of the trailing edge, the velocity defects shown in Figs. 4 and 5 followed the established x^(-1/3)
law for axisymmetric wakes.
1.0
u/Umain
0.8
0.6
0.4
z=1mm
x=0.04D
x=2D
x=4D
x=10D
0.2
0.0
-2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0
y/D
Figure 5.
Velocity distributions across the wake of 25mm diameter cylinder (L/D=6)
- 4 –
American Institute of Aeronautics and Astronautics