TM

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M-DAWModelling Design of Advanced Wing-tip
DevicesDr Chris Robinson

• TM CFD Meeting
• Nov 2003

To deliver to the European Aerospace Industry a
novel wing-tip device design to improve aircraft
efficiency and environmental impact together with
a capability to predict accurately the effect of
wing tip device design on aircraft performance
Airbus , Alenia, ETW, DLR, ONERA, NLR, TUBS, PW,
UMIST
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Wing Tip Device Research Industrial Context

• Induced drag is a significant element in overall
  aircraft drag
• Wing tip devices have been identified as a key
  technology to reduce emissions and noise,
  impacting all stages of flight
• And can be retrofitted on existing aircraft

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Wing Devices

• Crescent wing
• Swept wing tip
• Wing fence
• Winglet
• Wing tip sails
• Wing grid
• Spiroid
• O-wing

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Vortex generation NACA0012 case
Flow development Momentumless wake case
Far-downstream flow C-wake case
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UMIST Calculation Themes

• Vortex generation on wing-tip
• NACA 0012 half-wing, rounded wing-tip (Chow et al
  1997)
• 3d, elliptic, steady
• STREAM (Gambit/structured) SATURNE
  (ICEM/unstructured)
• Flow development in near-downstream region 0 lt L
  lt 30c
• Momentumless wake case (Sirviente Patel,
  1999,2000)
• 2d, elliptic, axisymmetric with swirl
• STREAM
• Flow in far-downstream region 20c lt L lt 300c
• Data from EU project C-wake
• 3d-parabolic

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Turbulence Models

• Linear EVM, k-? model (Launder Sharma, 1974)
• isotropic stress-strain, inappropriate for swirl
• Cubic non-linear EVM, k-? model (Suga, 1996)
• Stress anisotropy calculated by aijf(Sij,?ij)
• Calculated from local velocity gradients only
• Linear RSM (Gibson Launder, 1978)
• Linear treatment of pressure-strain
  wall-reflection term.
• Cubic non-linear RSM (Craft et al, 1996)
• Two-component limit model
• Rigorously enforces v2?0 at the wall, improved
  pressure-strain

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1. Vortex Generation- NACA0012 case

• Initial block structured grids
• STREAM1.8x106 cells
• SATURNE0.9x106 cells

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Vortex Generation STREAM Code Results - Pressure
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Vortex GenerationSATURNE Code Results -
U-velocity
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1.Vortex GenerationSATURNE Code Results -
Pressure
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1.Vortex GenerationVortex Centreline
Characteristics

• STREAM/structured STREAM/structured SATURNE/uns
  tructured

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2. Flow Development momentumless wake

• Patel Sirviente (1999, 2000)
• Series of experiments on momentumless wakes
• Non-swirling and swirling cases
• Detailed mean flow and turbulence data available

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2. Flow Development momentumless wake

• Non-swirling calculations on-going
• 2d RANS (fully elliptic)
• EVMs standard k-? cubic non-linear k-?
• SMCs Gibson-Launder (linear pressure-strain) Tw
  o-component limit (cubic pressure-strain)
• Currently introducing swirl to calculations

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2. Flow Development momentumless wake results
U-velocity
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2. Flow Development momentumless wake results
turb. energy half-width
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3. Far Downstream RegionC-wake Case

• Proposed calculations
• 2d and 3d parabolic RANS
• Data gathering
• Wind tunnel experiments
• Generic model, simple aircraft, 5-hole pressure
  probe, mean flow (U,V,W,P) turbulence data
  (?)10-15 spans (120c) downstream
• Towing tank experiments
• Similar model section, instantaneous data
  (U,V,W) 100-150 spans downstream, Re quite low

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Summary

• M-DAW
• Modelling Design of Advanced Wing-tip Devices
• EU collaboration, 9 industrial/research partners
• Integration with other projects FLOMANIA, C-Wake
• UMISTs involvement
• Provide expertise in turbulence modelling
• Study the effect of wing-tip device on vortex
  generation
• Calculate the far-downstream vortex
• Cases Studied
• Vortex generation on wing-tip NACA0012 half-wing
  STREAM/SATURNE
• Flow development in near-downstream region
  swirling, momentumless jet
• Flow in far-downstream region