Fig.3 The geometrical information of the separator and the observing fields adopted in PIV

3. Stereoscopic PIV measurement

Particle image velocimetry is a non-intrusive technique for the measurement of fluid velocity from an interest plane within a flow field. Double-exposure photography to record the position of seeding particles illuminated by a thin laser light sheet. The particle images are subsequently digitized in photographic film and analyzed using correlation techniques to obtain the velocity field.
Recent advances in PIV have been directed towards obtaining three-dimensional (3D) measurements of fluid velocity. Stereoscopic PIV method has been successfully demonstrated to acquire two simultaneous views along directions that perform with camera viewing angles of ±28º in present work. The apparent displacements recorded by each camera are later combined to obtain the correct in-plane displacement and the out-of-plane displacement. The stereoscopic PIV configuration for experimental measurements is shown in Fig. 4 and the schematic of stereo-vision is displayed in Fig. 5. All the specifications of stereo PIV and measurement details can be referred to Ref.[3].