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Granular Clustering in Reduced Gravity as a method of Asteroid Formation

Granular Clustering in Reduced Gravity as a method of Asteroid Formation. Aaron Coyner Astronomy Club of Tulsa University of Tulsa. Overview. What is Granular Collapse? Theoretical Explanation Applications Experimental Setup Methods of Reduced Gravity Experimental Operation

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Granular Clustering in Reduced Gravity as a method of Asteroid Formation

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  1. Granular Clustering in Reduced Gravity as a method of Asteroid Formation Aaron Coyner Astronomy Club of Tulsa University of Tulsa

  2. Overview • What is Granular Collapse? • Theoretical Explanation • Applications • Experimental Setup • Methods of Reduced Gravity • Experimental Operation • Results, Developments, and Future Tasks

  3. Granular Collapse • Proposed theory based on inelastic collisions within a granular gas state. • Granular gas • exhibit kinetic behavior like ideal gas • Collapse occurs as particle lose energy in collisions • clusters predicted near the center of the apparatus

  4. Granular Collapse Models • Two main types of experiments and models • HC regime • Homogeneous Cooling (No external energy) • Driven Systems • Driving mechanism input energy into the system • Both types have demonstrated collapse in 1-D and 2-D systems

  5. Relevance to Reduced Gravity • Inelastic Collapse of granular systems in reduced gravity could explain: • Asteroid Formation • Planetary Rings • Other celestial systems that could not for by gravitation alone.

  6. Experiment Goals • Visually Confirm Collapse in 3-D driven system • Determine parameters that influence collapse • Determine system dynamics before and after collapse • Determine time scales for collapse to occur

  7. The Gr.A.I.N.S. Experiment • Box set of 8 sample cells • Each cell ~1 in3 • Each cell contain varied number of brass ball • Sapphire walls • Each cell has an impact sensor • Impact data stored in external data drive • Mechanical Shaker System • Varies amplitude and frequency • Cameras and Mirrors • Cameras record video of 3 faces of the cube.

  8. Ways to Achieve Reduced Gravity • Sounding Rocket • Falcon et al. (1999) • Nasa’s KC-135 “Weightless Wonder” • Space Shuttle Flight • Get Away Special

  9. KC-135 Parabola

  10. Experiment Operation • Apparatus free floats in KC-135 Cabin • 5 to 7 second of unhindered free float • Operation almost fully automated • Free float allows for minimal acceleration due to the aircraft

  11. KC-135 Flight Days • Use different driving parameter program each day • Low frequency data show clustering in high density chambers • high frequency shaking remained kinetic at all times

  12. Video Evidence for Clustering

  13. Other Data • Impact Data shows random nature as expected for kinetic situation • Density appears influential in the cluster formation • Low density chambers showed no effects of inelastic collapse regardless of driving • No driving does not generate a granular gas

  14. Impact Data Sample

  15. Ongoing Work • Impact data are being analyzed to determine a value of the granular pressure for each sample. • Tracking software being implemented • Obtain velocity distribution • Modifications to experiment being made for GAS program shuttle flight

  16. Why Space Science is Fun

  17. The Gr.A.I.N.S. team Justin Mitchell Matt Olson Rebecca Ragar Jeffrey Wagner Erin Lewallen Justin Eskridge Adrienne McVey Nathan Jordan Ian Zedalis Shawn Jackson Dr. Michael Wilson Special Thanks to: Dr. Roger Blais Provost – Univ. of Tulsa Dr. Ken Kuenhold Physics Dept. Chair – Univ. of Tulsa Acknowledgements

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