Design and Development of a Smartphone-Based Particle Image Velocimetry System

Our research focuses on developing a smartphone-based Particle Image Velocimetry (PIV) system for use in educational and research purposes. Due to the high cost of components, a number of institutions across the world do not possess a PIV system for flow visualisation. Low-cost, accessible PIV systems are an essential requirement in such cases, which will also enable them to be included as a part of laboratory courseware for students. In our system, developed open-channel flow is visualised around a cylindrical body using smartphone cameras and low-intensity laser diodes. Hydrogen bubbles generated from electrolysis (termed Bubble Image Velocimetry) are used as a seeding medium. OpenPIV, an open-source MATLAB toolbox, is used to track particle motion and obtain flow profiles and velocities accurately, with flow separation and vortex formation being observed. A parametric analysis of smartphone cameras of different specifications is conducted, across varying camera characteristics such as ISO, exposure and frame rate. A base camera specification for PIV is hence determined. A low-cost (under USD 200), accessible yet accurate Particle Image Velocimetry system is so obtained.