Interactive Hele-Shaw cell for fluid mechanics instruction

Abstract

Fluid flow is inherently complex due to the nonlinear nature of its governing equations. Under special conditions, mathematical solutions result in potential flow, which can be analyzed using well-known methods. However, this is challenging to display on the conventional scale, which creates a barrier for new students of the subject. The classic Hele-Shaw cell provides a unique alternative for flow visualization. This device uses viscous flow through a pair of closely-spaced plates, mimicking irrotational potential conditions. We develop a novel version of this cell that incorporates a series of sources and sinks, which can generate flow around virtual shapes. Users arrange these ports in numerous configurations, ranging from simple flow solutions to unusual profiles relevant to aerodynamic systems. In principle, this cell can be used in different courses within the mechanical engineering curriculum, ranging from introductory to graduate level classes. We demonstrate the effectiveness of this device by evaluating student comprehension of flow past a series of common shapes. When comparing student performance before and after usage of the device, the average rating increased by more than 12%, which suggests a significant improvement in their understanding.