5 Experimental Fluid Mechanics
357
(3) Particle imaging velocimetry technique
Particle imaging velocimetry technique is developed under computer technology and graphics processing technique, and is an optical fluid measurement technique (as shown in Fig. 5.17). Since the 1950s, laser velocimetry
technique has been used and gradually formed on this basis. The biggest
advantage of this technique is that it breaks through the limitations of spatial
single-point measurement technique such as laser Doppler velocimetry, which
not only has the accuracy and resolution of single-point measurement technique, but also can obtain the overall structure and transient image of planar
or spatial flow field display. The information about the entire flow field can
be recorded at the same time, and the average speed, the pulsation speed,
etc., can be, respectively, given, which is a non-contact measurement method.
The basic principle is: the particles are placed in the flow field during the
experiment, and the laser beam emitted by the pulsed laser forms a modulated laser irradiation flow field through a series of optical elements, and
the images of the particle field at different times are recorded by multiple
exposures. By measuring the displacement L of each particle at t time
interval, the velocity of the particle can be calculated. Under the condition
Fig. 5.17 Particle imaging velocimetry technique
357
(3) Particle imaging velocimetry technique
Particle imaging velocimetry technique is developed under computer technology and graphics processing technique, and is an optical fluid measurement technique (as shown in Fig. 5.17). Since the 1950s, laser velocimetry
technique has been used and gradually formed on this basis. The biggest
advantage of this technique is that it breaks through the limitations of spatial
single-point measurement technique such as laser Doppler velocimetry, which
not only has the accuracy and resolution of single-point measurement technique, but also can obtain the overall structure and transient image of planar
or spatial flow field display. The information about the entire flow field can
be recorded at the same time, and the average speed, the pulsation speed,
etc., can be, respectively, given, which is a non-contact measurement method.
The basic principle is: the particles are placed in the flow field during the
experiment, and the laser beam emitted by the pulsed laser forms a modulated laser irradiation flow field through a series of optical elements, and
the images of the particle field at different times are recorded by multiple
exposures. By measuring the displacement L of each particle at t time
interval, the velocity of the particle can be calculated. Under the condition
Fig. 5.17 Particle imaging velocimetry technique