Design and characterization of a low-cost particle image velocimetry system

Particle Image Velocimetry (PIV) is considered the gold standard technique for flow visualization. However, its cost (at least tens of thousands of dollars) can prove inhibitive in its standard form. This article presents an alternative design, leveraging off-the-shelf and open-source options for each key component involved: camera, laser module, optical components, tracer particles, and analysis software. Flow visualization is a crucial technique to connect theory to practice in teaching and researching fluid mechanics. Despite the ubiquity of this field within engineering curricula, many undergraduate institutions globally forego utilizing such equipment, given the barriers to setting it up. The availability of this low-cost alternative (∼$500) that can be built in-house offers a path forward. Characterization was done by visualizing the rotational flow generated by a magnetic stirrer in a cylindrical beaker. The velocity magnitude around the stirrer bar measured by the low-cost PIV system was compared to expected values calculated analytically. The percent difference was between 1–2% when the flow stayed two-dimensional but increased as the flow began developing into more of a 3-D flow. Repeatability varied no more than 6% between experiments. This platform holds the potential for reliable replication across institutions broadly.