Paper 6.4
Simultaneous Measurement of All the Three Components of Vorticity Vectors by
Using a Dual-plane Stereoscopic PIV System
Tetsuo SAGA 1), Hui HU1), Toshio KOBAYASHI1),
Nubuyuki TANIGUCHI1), Masashi YASUKI2) and Taizo HIGASHIYAMA3)
1. Institute of Industrial Science, University of Tokyo, 7-22-1 Roppongi, Minato-ku,
Tokyo 106-8558, Japan
2. Industrial Instruments Department, SEIKA CORPORATION, 1-5-3 Koraku, Bunkyo-ku, Tokyo Japan
3. Fluid Measuring Instrument Division, KANOMAX JAPAN, INC., 3-18-20 Nishishinjyuku, Tokyo160, Japan
E-mail: saga@.iis.u-tokyo.ac.jp or huhui@cc.iis.u-tokyo.ac.jp
ABSTRACT
The technical basis and system set-up of a dual-plane stereoscopic PIV system, which can obtain the flow velocity (all
three components) fields at two spatially separated planes simultaneously, was described in the present paper. The
simultaneous measurements were achieved by using two sets of double-pulsed Nd:Yag lasers with other optics to
illuminate the objective fluid flow with two orthogonally linearly polarized laser sheets at two spatially separated
planes. The scattering lights from the two illuminating laser sheets with orthogonal linear polarization were separated
by using polarizing beam splitter cubes, then recorded by high-resolution CCD cameras. Unlike conventional twodimensional PIV systems or single-plane stereoscopic PIV systems, which can just get one-component of vorticity
vectors, the present dual-plane stereoscopic PIV system can provide all the three components of the vorticity vectors
and various auto-correlation and cross-correlation coefficients of flow variables instantaneously and simultaneously.
The present dual-plane stereoscopic PIV system was applied to measure an air jet mixing flow exhausted from a lobed
nozzle to demonstrate its feasibility. In order to evaluate the measurement accuracy of the present dual-plane
stereoscopic PIV system, the measurement results of the present dual-plane stereoscopic PIV system were compared
with the simultaneous measurement results of a LDV system. It was found that both the instantaneous data and
ensemble-averaged values of the stereoscopic PIV measurement results and the LDV measurement results agree with
each other well. For the ensemble-averaged values of the out-of plane velocity component at comparison points, the
differences between the stereoscopic PIV and LDV measurement results were found to be less than 2%.
Key words: Stereoscopic PIV technique, Simultaneous measurement of the all three components of velocity and
vorticity vectors, The measurement of auto-correlation and cross-correlation coefficients of flow
variables, Polarization separation of laser beams, Lobed jet mixing flow.
2 0 m /s
2 0 m /s
Y
Y
20
20
0
X
0
-20
Y mm
Z
Y mm
X
-20
-30
-30
-20
-20
-1 0
-1 0
0
0
a. Instantaneous result at Z=10mm plane
b. the simultaneous velocity field at Z=12mm cross plane
30
30
1
3
74
65
2
7 31
1
2
3
1
5
6
9
3
3 7
4
3
2
8
6
9
7
Y mm
3
2
6
8 7 1
3
2
5
96 7 1 3
8
4
13
2
5
2
4
2
4
4
5
3
5 1
13
4 3
3. 0
6
5
9 974
81 15 1
4
4
5. 0
4. 0
1
74 8
3
2
7
3
-20
3
1
-10
3
-3 0
7. 0
6. 0
3
2
4
56
-5 . 00
9. 0
8. 0
5
4
3 7 47
5
4 5 13
2
1
1 1. 0
1 0. 0
7
6
6
6
-1 . 00
-3 . 00
1 3. 0
1 2. 0
9
8
4
7
3
2
7
2
4
5
11
4
3 . 00
1 . 00
13
2
5
5
4
2
0
6
4
2
5
4
2
23
5 . 00
1 5. 0
1 4. 0
11
10
2
3
4
4
6
13
12
118
6
1 06
5 3
4
6
-2 0
v or t icit y di st rib u ti on
( Z -c o m p o ne n t)
4
5
-1 0
8
13
9
5
35 4
64
4
3
4
2
3
7
10
3
3
65
5
4
2
0
3
10
T h e st r en g th o f
in - p lan e v o rt icit y
9
4
2
4
20
5
5
4
3
2
2
3
53
6
5
4
13
65
4
20
2
4
3
Y mm
Z
5
4
-30
-4 0
-40
-2 5
0
25
50
X mm
c. Instantaneous streamwise vorticity field
- 40
- 20
0
20
X mm
40
d. instantaneous in-plane vorticity distribution