256
11 Non-intrusive Measurement Techniques
(a) Instantaneous velocity
(b) Correlation coefficient of the streamwise
vorticity in the mixing layer
Fig. 11.18 Measurement of the velocity fluctuation in the mixing layer of a turbulent round jet
using stereoscopic PIV for 3 components measurement (© ONERA)
11.6.4 PIV Tomography or PIV 3D
Around the mid-2000 tomographic or volumetric PIV started appearing; this enabled
measurement of a three-dimensional flow field (3D3C). As shown in Fig. 11.19, in
this technique the thickness of the laser sheet is increased using another set of lens to
produce a volume (10–20 mm wide) in which the flow is captured using 3–4 cameras
at least.
Fig. 11.19 Schematic representation of the processes involved in tomographic PIV
11 Non-intrusive Measurement Techniques
(a) Instantaneous velocity
(b) Correlation coefficient of the streamwise
vorticity in the mixing layer
Fig. 11.18 Measurement of the velocity fluctuation in the mixing layer of a turbulent round jet
using stereoscopic PIV for 3 components measurement (© ONERA)
11.6.4 PIV Tomography or PIV 3D
Around the mid-2000 tomographic or volumetric PIV started appearing; this enabled
measurement of a three-dimensional flow field (3D3C). As shown in Fig. 11.19, in
this technique the thickness of the laser sheet is increased using another set of lens to
produce a volume (10–20 mm wide) in which the flow is captured using 3–4 cameras
at least.
Fig. 11.19 Schematic representation of the processes involved in tomographic PIV