Classroom demonstration of a stagnation flow using cell phone-captured particle image velocimetry data

Abstract

Courses in fluid mechanics and aerodynamics often require lengthy and involved mathematical derivations. However, these subjects are also associated with visually appealing flow features. In an effort to provide students with a full appreciation for fluid mechanics, it is desirable to not only provide a theoretical background, but also perform some visual demonstrations; this can be achieved through quantitative flow visualization demonstration. The cost of research-grade equipment is prohibitive for a teaching college, especially if only used for classroom demonstration. This article describes a Particle Image Velocimetry (PIV) demonstration of flow around a vertical plate using widely available cell phone cameras, reducing the cost of the required equipment. The velocity field calculated using PIV analysis was compared to a velocity field predicted using potential flow theory. The two showed an agreement of about 30% – a sufficient accuracy for an in-classroom demonstration. The learning effectiveness of this demonstration was evaluated using course evaluations and an end-of-semester survey. Overall, students expressed their appreciation for added experimental work and visualization to the course curriculum.