Particle Image Velocimetry
Particle Image Velocimetry (PIV) is a non-contact optical measurement technique used to visualize and analyze fluid flow by tracking the motion of small tracer particles suspended in the fluid.
How It Works
- Seeding the Flow
- The fluid (air, water, etc.) is “seeded” with tiny tracer particles that follow the motion of the fluid accurately without affecting its behavior.
- Illumination
- A laser sheet is used to illuminate a thin cross-section of the flow. Pulsed lasers are often used so that two images can be captured in rapid succession.
- Imaging
- A high-speed or double-frame camera captures two images of the particles at a known time interval.
- Data Processing
- Special cross-correlation algorithms analyze the displacement of particles between the two images to determine velocity vectors throughout the flow field.
Applications
- Aerospace – Studying airflow over wings, propellers, or jet engines.
- Automotive – Measuring flow inside combustion chambers or around vehicle bodies.
- Biomedical – Blood flow studies in research and diagnostics.
- Industrial – Optimizing mixing, spray patterns, or flow in pipelines.
- Environmental – Measuring currents in rivers, ocean waves, or atmospheric flows.
Why PIV is Powerful
- Non-intrusive – Does not disturb the flow like physical probes might.
- Full-field measurement – Provides velocity information over a 2D or 3D area, not just at a single point.
- High resolution – Can capture rapid and complex flow phenomena when paired with high-speed cameras. (Note: Add the PIV diagram image from the document here)