What is Particle Imaging Velocimetry?
Particle Imaging Velocimetry (PIV) is a non-intrusive, laser optical measurement technique used in research and diagnostics of flow turbulence, microfluidics, spray atomization, and combustion processes. Particle imaging velocity measures the entire region within the flow with simultaneous measurement of its velocity.
The basic principle includes photographic recording of the motion of microscopic particles that follow the fluid or gas flow. Image processing techniques then ascertain the particle motion and the flow velocity from the photographic recordings. As long as there are enough particles inside the area of flow under examination the complete velocity field of the flow can be determined.
This highlights the differences between PIV and point measurement methods, which use probes to measure flow velocity at a single point. The main benefit of PIV is that it is a quantitative flow field mapping method, which can offer physical insight into the complete flow behavior. PIV enables both the extraction of measurement data and the visualization of flow structures.
The standard particle image velocimetry set up comprises a high-speed camera, a high-power multi-pulsed laser, and an optical arrangement to transform laser output light to a light sheet and a synchronizer, which controls the synchronization of the laser and the camera.
Applications for Particle Imaging Velocimetry?
Particle image velocimetry is an experimental tool in the fields of aerodynamics and fluid mechanics. By offering a near-instantaneous velocity field, particle imaging velocimetry offers the benefits of a flow visualization technique, while also offering critical quantitative information. After ascertaining the velocity field, data like vorticity and strain can be easily found along with the turbulence intensity.
In aerodynamics, particle imaging velocimetry is helpful in understanding unsteady flow phenomena. PIV can measure aircraft wake vortices of a lifting wing, investigate rotor aerodynamics with noise emission of a range of noise sources, and measure transonic flow over airfoils. This application is a growing area of interest as airports reach higher capacities and takeoffs and landings become more frequent. Wake vortex effects have also caused numerous aircraft mishaps. PIV is therefore important to understand the efficiency of airports.
PIV is also employed in the investigation of liquid flows, such as the vortex-free-surface interaction, thermal convection and Couette flow between concentric spheres.
A range of Laser Quantum lasers are suitable for particle imaging velocimetry (PIV), but listed below are a series of lasers across a range of powers.
- gem – Small light sheets delivering up to 2 W (gem family datasheet)
- opus – Higher power up to 6 W for larger sample areas (opus family datasheet)
- finesse – Highest power for the larger samples (finesse family datasheet)
To request more information or a quotation for these or other Laser Quantum products, contact IL Photonics.