Gibson, E. G.

English

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158 
SIfYLBB kUID MeCEANICS DEMONSTRATIONS 
d 
bY 
Edward G. Gibson 
Science Pilot, Skylab 111 
The substance of this presentation is a motion picture film which 
illustrates some of the fluid mechanics demonstrations accomplished on 
the Skylab missions. 
taken in flight, most of which is from the third and last manned misaion. 
These demonstrations were conducted on an unscheduled basis whkever a 
It is representative of the many hours of data 
member of the crew, usually the science pilot, could make some time 
available. 
for flight until very late relative to the other Skylab experiments, the 
amount of crew familiarization and training, additional hardware and 
inflight t h e  which could be made available were minimal. 
Because these demonstrations were not proposed and approved 
The improvement in the techniques of handling fluids in zero 
gravity during the course of the three missions is first shown. 
light thread was sometimes used to stabilize fluid drops. 
with large openings were found to be useful for dispensing the fluids. 
Ink or small amounts of drink juices were often added to water to 
provide better visualization. 
onboard television system. 
lens provided excellent viewing of the investigations. 
phenomena to be explored also increased significantly with each mission. 
A very 
Syringes 
Most of the data was taken with the 
On the last flight the use of a close-up 
The list of 
The modes of oscillation of a fluid droplet on a flat plate were 
then presented. The drop was perturbed by either oscillation of the 
https://ntrs.nasa.gov/search.jsp?R=19820066621 2020-03-21T06:53:24+00:00Z
p l a t e  o r  by impfngmeut 
perwndicdar  t o  the plate. The motions of the drop were followed through 
Ipaog cycles t o  pernrit study of the  damping and devalopmant of modes of 
osc i l la t ion  different  than the one excited. 
of a jet of air from above the drop and directed 
A large portion of the fi lm i l l u s t r a t e8  the characteristics of f lu id  
spheres i n  zero gravity. 
Each sphere was perturbed spmnatrically about a plane through the centar 
of the  sphere and the modes of osc i l la t ion  and damping were followed. 
Spheres of a water-soap mixture or  of a low density soap f ro th  were 
obsemed t o  dgmonatrate the a f fec ts  of changes in density, viscosi ty  and 
surface tension on the  modes of osc i l la t ion  and damping. 
were rotated and fission of tha. sphara was observed. With rotat ion of a 
sphere, a "dog bone" geometry developed before fission. 
was never observed. 
Different re la t ive  drop sizes, veloci t ies  and impact parameters were used. 
Lastly, air was injected into water spheres so that a "sphere Within a 
sphere" was obsemed. 
fn damping of sphere osci l la t fons was observed. 
Sphere sizes approximately 5 t o  20 cc w e r e  used. 
Water spheres 
A toroidial  form 
Collisions bemeen water drops were also studied. 
Bubble collapse and the very pronounced increase 
The largast  f ract ion of e f fo r t  was directed at  the  study of l iquid 
f loat ing zones, a denmatration suggested end developed by Dr .  3. 8. 
Carruthers of B a l l  Laboratories. 
w a r e  s tabi l ized between two circular plates  of 7/8 inch diameter. 
f l u id  91118 allowed t o  w e t  the  f l a t  surface of each p la te  but was prevented 
from wetting the edges by we of Krptox lubricant. 
Cylinders of 6 ,  14, and 20 cc of f lu id  
The 
"he plates  w e r e  then 
160 
rotated at  various speeds in ei ther  the same direction or  opposite 
directions and the resultant f lu id  motions observed. 
observed ins tab i l i ty  was  a bowing of the cylinder o r  "C shaped" 
instabi l i ty .  
used in addition t o  colored water. 
cylindrical  water column. The coalescence of the bubbles, t he i r  moveanent 
t o  the center of the axis of rotat ion and the i r  effect  of increasing the 
damping of the column were observed. Longitudinal vibration, that is, 
The most connuonly 
Mixtures of soap and water and a soap f ro th  were again 
Bubbles were also injected in to  the 
vibration of the end p l a t e s  along the axfs of the colunm, was  studied with 
each column before rotation. When the  vibration was of the correct f r r  
quency, standing waves were observed. 
duced an increase in the number of modes observed. In order t o  a id  in flow 
visualization, soap fragments were added t o  clear water columns in several 
runs. Lastly, the maximum theoretical  s table  column length of TT times the 
diameter (2.75 inches) w a s  observed t o  be s l igh t ly  exceeded (2.90 inches) 
but the shape was tha t  of an uuduloid which s l igh t ly  increased the s t ab i l i t y  
and made it possible. 
A n  increase i n  the frequency pro- 
The f luid mechanics demonstrations conducted on Skplab only scratched 
the surface of the useful f luid mechanics experbents  that  can and should 
be done on future shut t le  raissions i n  the 1980's. 


Skylab fluid mechanics demonstration

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