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The conquest of Weightlessness Collection of Presentations Danail Obreschkow, Feb. 2006
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Feel Weightlessness & Gravity Insight in 0g-Research GOALS
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1 Weightlessness 2 Cavitation 3 Sensations 4 Results 5 Next Step 6 Beyond
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Weightlessness and Free Fall 1
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Weightlessness = Free Fall Weightlessness = Free Fall ≠ Zero Gravity Inertial force Gravitational force Gravitational force Inertial force Net Force Weightlessness = Free Fall = Zero Gravity Gravitational force Gravitational force No net Force
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Free Fall Trajectories
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Free Fall Technologies Drop Tower 5 seconds Parabolic Flight 25 seconds Sounding Rocket 12 minutes Space Ship weeks
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Who ? etc.
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Why ? BiologyFluid dynamics Medicine & Psychology Physics & Chemistry
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About Cavitation 2
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Phenomenon of Cavitation Tiger Pistol Shrimp: Shockwave kills small fish in 2 meters distance !
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Cavitation in Technology Damage Concerned Technologies Questions: Last Stage of Cavity Collapse ? Interactions with Surfaces ?
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Last Stage of Collapse Shock WaveMicrojetSonoluminescence”Cold” Fusion Supersonic 10-100 GPa Subsonic-sonic Sharp Point-like 10 4 -10 6 K Erosion Vibration Efficiency loss ???
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Interaction with Free Surface
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Experimental Access Problems: Water volume never isolated Free surfaces always flat + – Electrical discharge Laser
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Goal Confined shockwave Observe all liquid jets Interaction with spherical free surface Water Drop Cavitation Bubble NB: Drawn before the experiment !
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Setup
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Functional Units
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Drop Formation & Fixation
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Here we go !
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Sensation of Weightlessness 3
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Flight Maneuver 31 parabolas per flight inside a military flight zone
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Movies
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Phenomenology Initial stomach lift No up, no down Feather weight – Stone mass
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Below and above
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Above and below
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Medical aspects Scopolamin Promethazin
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Results 4
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Real Motion 10 mm
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Slow Motion 10 mm
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Ultra Slow Motion 10 mm
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Drop Formation 1/e damp out time = 0.7s Negligible interaction Repulsion by electrodes Attraction by electrodes
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Stability of Drop and Free Surface
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Bubble Size Evolution Model Experiment Validation Prediction
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Counterjet Geometry Planar free surface (ground experiment) Spherical free surface (microgravity experiment) bubble [Robinson et al. 01] Free Surface High pressure Numerical Simulation
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Shockwave-Nuclei Interaction 0.0ms0.08ms0.16ms Shockwave Energy New channel for erosion
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Jet-pair Instabilities Counterjet Geometry Bubble Collapse Shock Wave Unexpected Hair-jets
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Next Step 5
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Catch the Shock Wave !
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Sparkling Water
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Beyond… 6
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Dilemma of Choice
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Symbol of Political Power
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Ozone Hole Sep 18, 1979Sep 17, 2001
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UESCO World Heritage Site Iguaçu 19732001
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