Tracking the Movement of Hydrogen Bubbles in Turbulent Flow

This project was designed to gain insight into the role of turbulent flow (instantaneous stress tensor) in the movement of sediment particles along a river bed. Improved understanding of such a phenomeinon would facilitate the design of river related structures, such as flood control schemes and dams, and minimize potentially detrimental effects to the environment. This particular experimental analysis technique tracks the motion of hydrogen bubbles, that are created in a stream of water by using an electrolysis method.

The experiment was filmed from above, so we are only looking at 2 dimensions of the chaotic motion. The film was then digitized, using a SGI Indigo with a video card, there were approximately 300 video frames captured, ~ 5 seconds of real time video. The resulting video file was then taken apart into individual frames. These frames were then transfered to a SUN workstation and analyzed using custom written PV-Wave code. This PV-Wave program displayed sequential frames from the video and wrote out the xy coordinates of selected bubbles. Altering the color palette allowed for easier discrimination between the individual bubbles. You can view a GIF Image of this. You can also view a MPEG movie of the actual sequence of images. The same technique will be used to track the motion of sediment particles in a laboratory flume.

This work, part of a larger study, supported by the Fluid Particle and Hydraulic Systems Program of NSF, was conducted by Thanos Papanicolaou and Dr. P. Diplas.

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