The conquest of

Weightlessness

Collection of Presentations

Danail Obreschkow, Feb. 2006

Feel Weightlessness & Gravity

Insight in 0g-Research

GOALS

1 Weightlessness

2 Cavitation

3 Sensations

4 Results

5 Next Step

6 Beyond

Weightlessness

and

Free Fall

1

Weightlessness = Free Fall

Weightlessness = Free Fall ≠ Zero Gravity

Inertialforce

Gravitationalforce

Gravitationalforce

Inertialforce

Net Force

Weightlessness = Free Fall = Zero Gravity

Gravitationalforce

Gravitationalforce

No net Force

No net Force

Free Fall Trajectories

Free Fall Technologies

Drop Tower

5 seconds

Parabolic Flight

25 seconds

Sounding Rocket

12 minutes

Space Ship

weeks

Who ?

etc.

Why ?

Biology Fluid dynamicsMedicine & Psychology

Physics & Chemistry

About Cavitation2

Phenomenon of Cavitation

Tiger Pistol Shrimp: Shockwave kills small fish in 2 meters distance !

Cavitation in Technology

Damage

Concerned

Technologie

s

Questions:Last Stage of Cavity Collapse ?

Interactions with Surfaces ?

Last Stage of Collapse

Shock WaveMicrojet Sonoluminescence ”Cold” Fusion

• Supersonic

• 10-100 GPa

• Subsonic-sonic

• Sharp

• Point-like

• 104-106 K

Erosion

Vibration

Efficiency loss

???

Interaction with Free Surface

Experimental Access

Problems: Water volume never isolated

Free surfaces always flat

+ –

Electrical discharge

Laser

Goal

Confined shockwave

Observe all liquid jets

Interaction with spherical free surface

Water Drop

Cavitation Bubble

NB: Drawn before the experiment !

Setup

G-Sensor Input InterfaceOutput Interface Photron CameraControl Unit

Audio

USB

Firewire

TTL PulseGenerator

MicropumpElectrodeDischargeGenerator

Electrodes

TTL PulseGenerator

CordinDischargeGenerator

Flashlight

Banana

TTL (BNC)

TTL (BNC)

TTL (BNC)

24V (BNC)

TTL (BNC)

Button

Banana

5DCBanana

USB

Photro Camera

220ACComputer Plug

220ACComputer Plug

220ACComputer Plug

220ACSwiss Plug

5DCBanana

24DC220AC

Computer Plug

12DC

220ACSwiss Plug

PCMICA

Functional Units

Drop Formation & Fixation

Here we go !

Sensation of

Weightlessness

3

Flight Maneuver

31 parabolas per flight

inside a military flight zone

Movies

Phenomenology

Initial stomach lift

No up, no down

Feather weight – Stone mass

Below and above

Above and below

Medical aspects

Scopolamin

Promethazin

Results4

Real Motion

10 mm

Slow Motion

10 mm

Ultra Slow Motion

10 mm

Drop Formation

1/e damp outtime = 0.7s

Negligible interaction

Repulsionby electrodes

Attractionby electrodes

Stability of Drop and Free Surface

Bubble Size Evolution

ModelExperiment

ValidationPrediction

Counterjet Geometry

Planar free surface(ground experiment)

Spherical free surface(microgravity experiment)

bubble bubble

[Robinson et al. 01]

Free Surface

High pressure

Numerical Simulation

Shockwave-Nuclei Interaction

0.0ms 0.08ms 0.16ms

Shockwave Energy

New channel for erosion

Jet-pair Instabilities

Counterjet

Geometry

Bubble

Collapse

Shock

Wave

Unexpected

Hair-jets

Next Step5

Catch the Shock Wave !

Sparkling Water

Beyond…6

Dilemma of Choice

Symbol of Political Power

Ozone Hole

Sep 18, 1979 Sep 17, 2001

UESCO World Heritage Site Iguaçu

1973 2001