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11 Non-intrusive Measurement Techniques
(a) Image of the particles in the laser sheet
(b) Velocity field after processing
Fig. 11.15 Result of PIV processing
Fig. 11.16 PIV measurements in the wake downstream of a car model, showing the contours of
the mean streamwise velocity (© PRISME Laboratory)
11.6.3 Three Components Stereo PIV
The advent of stereoscopic PIV in the mid-90s allowed for the measurement of
three velocity components in the 2D plane of the light sheet. Here, the light sheet
is slightly thickened with respect to the case of planar PIV so as not to lose particle
pairs during the two pulses of illumination. The visualisation is through two cameras
positioned each at an angle to the plane of the laser sheet, following a slightly more
involved alignment process, a calibration and perspective correction the out-of-plane
(normal to the plane of the laser sheet) displacement can be determined. A schematic
representation of the stereo PIV set-up is shown in Fig. 11.17; this is for the study of
the dynamics of fluctuating structures within a mixing layer generated from a round
11 Non-intrusive Measurement Techniques
(a) Image of the particles in the laser sheet
(b) Velocity field after processing
Fig. 11.15 Result of PIV processing
Fig. 11.16 PIV measurements in the wake downstream of a car model, showing the contours of
the mean streamwise velocity (© PRISME Laboratory)
11.6.3 Three Components Stereo PIV
The advent of stereoscopic PIV in the mid-90s allowed for the measurement of
three velocity components in the 2D plane of the light sheet. Here, the light sheet
is slightly thickened with respect to the case of planar PIV so as not to lose particle
pairs during the two pulses of illumination. The visualisation is through two cameras
positioned each at an angle to the plane of the laser sheet, following a slightly more
involved alignment process, a calibration and perspective correction the out-of-plane
(normal to the plane of the laser sheet) displacement can be determined. A schematic
representation of the stereo PIV set-up is shown in Fig. 11.17; this is for the study of
the dynamics of fluctuating structures within a mixing layer generated from a round