fairfolio
Saved Projects

Persistent Holes in Non-Newtonian Fluids

CSEF · 2005 Aerodynamics/ Hydrodynamics

Kristin E. Barker · Presentation High School, San Jose

Overview

Objectives/Goals The objective of this project is to induce persistent holes in non-Newtonian fluids and to understand the dynamics of fluid behavior under the application of shear force. Methods/Materials Experiments were performed by vertically shaking a variety of Newtonian and non-Newtonian fluids (shear-thickening and shear-thinning) in an acoustically driven vertical shaker. Air puffs were administered to the agitated fluid, and if holes were obtained, they were quantified. Results Persistent holes were not obtained in the Newtonian fluids; however, persistent holes were produced in the non-Newtonian fluids. They were found in both the shear-thickening and shear-thinning fluids, but appeared to be of different character and driven by different processes. The appearance of persistent holes in shear-thinning fluids extends the known published literature. Complex hole dynamics were observed in the shear-thickening fluids that were studied. Conclusions/Discussion The holes formed in the shear-thinning fluid appear to result from processes different from those which produce holes in shear-thickening fluids. The holes formed in the shear-thinning fluid appeared at lower frequencies, and they could be induced spontaneously. The graph of lifetime versus frequency reveals a threshold at which a hole can be determined to be persistent. However, the system dynamics are so complex that this threshold is highly variable for the holes observed. By viewing the video recordings of holes in shear-thickening fluids at an accelerated frame rate, it was observed that the diameters of the persistent holes oscillated slowly in time with small amplitude. Review of the video recordings of holes in shear-thinning fluids revealed a torodial wall structure in which fluid was observed to move more rapidly than in the surrounding regions. Faraday waves were observed to be present when persistent holes were induced in both shear-thickening and shear-thinning fluids. The results of these experiments agree with the known published literature, and the results for the shear-thinning fluids extend the known published literature. Areas for further investigation were identified, including the application of shear-thickening fluids to infantry-soldier body armor and design of antiterrorist patrol vehicles.

Summary statement

Persistent holes can be induced and sustained in both shear-thickening and shear-thinning non-Newtonian fluids, and shear-thickening fluids have practical applications in personal and vehicular armor.

Help received

Dr. John C. Howe and Dr. Charles Barker provided supportive mentoring. Also, they provided ongoing supervision to ensure that proper safety procedures were followed during experimentation. The tests were completed at Aurora Networks, Inc. in Santa Clara, California.

Awards (1)

  • Category Award

Competition history

  • CSEF 2005 Aerodynamics/ Hydrodynamics · Entry S0102

Resources

Related projects

Closest projects by meaning, across every fair and year in the corpus.

Browse more like this

Source: California Science & Engineering Fair public projects

Save projects to your library

Sign in with Google to keep track of projects you find interesting, organized into folders. An account also raises your daily allowance for “Has this been done?”, and lets you create a key for the MCP server with a much higher limit than anonymous use. Browsing stays public.

Continue with Google