AIR FLOW AROUND MOVING SURFACE

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AIR FLOW AROUND MOVING SURFACE

• Jaroslav PELANT
• Aeronautical Research and Test Institute
  Prague/CZ
• Karel ADÁMEK
• Textile Machines Research Institute Libere/CZ

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• The paper describes the method of air flow
  numerical modelling around moving rigid surfaces
  and presents results of two solved applications
• Flow around oscilating NACA profile at high
  subsonic velocities, using angle of attack range
  from 3 to 3 periodically changing with
  frequency range 15 50 Hz .
• b) Flow induced by rotation of dented drum used
  on carding machine in textile industry,
  circumferential velocity of 40 m/s.
• Developed method is suitable for wide range of
  velocities without any complications.

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• CASE 1 Flow around oscillating profile
• The position of shock wave in solved flowfield
  around given profile depends on
• angle of attack
• frequency of oscillations
• movement direction (up/down).
• They are presented results of lower position
  (-3, up), results of symmetrical upper position
  (3, down) are symmetrical, too.

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Angle of attack 0, motion up, 15 Hz
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Angle of attack -3, motion up, 15 Hz
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Angle of attack -3, motion up, 30 Hz
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Angle of attack -3, motion up, 50 Hz
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CASE 2 Fowfield induced by rotating dented
drum Interesting results of flowfields given by
interaction of rotating drum with various
surroundings used in textile technology.
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AIR FLOW
INDUCED BY ROTATING DENTED SURFACE

(velocity isolines in the middle part
of model)
smooth standing surface (gap 0,5...2 mm)
dented moving surface
(drum diameter of 1,2 m,
circumf. velocity 40 m/s to right)
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AIR FLOW INDUCED BY DENTED SURFACE (velocity
isolines)
Interesting detail of velocity field development
at the beginning of solved area not for
practical use
smooth standing surface
dented moving surface
(drum diameter 1,2 m,
circumf. velocity 40 m/s to right)
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AIR FLOW INDUCED BY DENTED SURFACE
(circumferential velocity isolines)
standing surface - dented, gap of 0,3 mm
moving surface (40 m/s to right, dented - pitch
of 1,3 mm)
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AIR FLOW
INDUCED BY ROTATION OF DENTED SURFACE
(radial velocity isolines)
standing surface - dented, gap between dent tips
0,3 mm (expressive
vortexes)
moving surface (40 m/s to right, dented - pitch
of 1,3 mm)
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AIR FLOW (velocity isolines)
INDUCED BY
ROTATION OF DENTED SURFACES
(outer
contact inlet part)
dented moving surface II (some air volume is
flowing back to tle left from the central
wedged part)
dented moving surface I, both surfaces 40 m/s to
right
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AIR FLOW (velocity isolines)
INDUCED BY ROTATION
OF DENTED SURFACES
(outer contact
middle part)
dented moving surface II (expansion of air volume
closed between rotor and stator)
dented moving surface I, both surfaces 40 m/s to
right
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AIR FLOW (velocity isolines)
INDUCED BY ROTATING
DENTED SURFACES
(outer contact
middle part - detail)
Some air volume is compressed in the area between
stator and rotor in their nearest positions and
is expanding from just opened gap between dent
tips of rotor and stator.
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AIR FLOW (velocity isolines)
INDUCED BY ROTATING
DENTED SURFACES
(outer contact
outlet part)
dented moving surface II (suction of some air
volume back to tle left from surroundings in
the central wedged part)
dented moving surface I
both surfaces (40 m/s
to right, dent pitch 1,3 mm)
It is possible to suppress observed backflow
introducing rigid
bodies of suitable shape
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Conclusion Presented results of numerical
modelling are in good coincidence with
experiments and/or practical trials. They can be
used for design of new practical
application. Thank you for your attention.