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Transonic Buffet Control on 3D Turbulent Wings using Fluidic Devices

Part 1: Open loop study

J. Dandois 1, J.-B. Dor 2, P. Molton 3, A. Lepage 4 F. Ternoy 5, V. Brunet 1 and E. Coustols 2

1 Applied Aerodynamics Department 2 Aerodynamics and Energetics Modeling Departement 3 Fundamental and Experimental Aerodynamics Department 4 Aeroelasticity and Structural Dynamics Department 5 Model Design and Manufacturing Department

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Buffet phenomenon

- Buffet limits operational flight conditions of a given aircraft (Mach number, lift), which leads to a margin (30%) between CLcruise and CLbuffet_onset - Buffet control would provide more flexibility in wing design

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Plan

1) S3Ch wind tunnel tests (PRF BUFET’N Co & JTI SFWA WP112) => “research-type” tests to compare the efficiency of passive and

active VGs => acquisition of an extensive database for the validation of numerical

simulations (unsteady pressure transducers, PIV and LDV) => preparation of the S2MA WTT

1) S2MA wind tunnel tests (EC FP6 AVERT & PRF BUFET’N Co ) => final demonstration of the buffet control in an industrial-type wind

tunnel (open loop & closed-loop)

Testing of active devices at the ONERA S3Ch WT Mechanical VGs Fluidic VGs: small nozzle M=2, Φ=1mm (continuous/pulsed)

S3Ch wind tunnel tests

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Flow control by mechanical VGs: α = 3.5°, Mp = 0.815

80% 70% 60% 50% Baseline

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Flow control by fluidic VGs: α = 3.5°, Mp = 0.815

80% 70% 60% 50% - Flow separation suppressed between Y/b = 60 and 80% - Results similar to mechanical VGs

Baseline

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y/b=70%-1.5

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-0.5

0

0.5

1

0 10 20 30 40 50 60 70 80 90 100

x/c(%)

-Kp

Baseline

2g/s (Cmu=2.3e-4)

1.8g/s (Cmu=2.1e-4)

1.6g/s (Cmu=1.8e-4)

1.35g/s (Cmu=1.5e-4)

1.2g/s (Cmu=1.4e-4)

1.1g/s (Cmu=1.3e-4)

1g/s (Cmu=4.3e-5)

0.8g/s (Cmu=3.4e-5)

0.7g/s (Cmu=2.2e-5)

0.5g/s (Cmu=1.1e-5)

JTI-SFWA 1.1.2 : S3Ch Wind Tunnel Tests

• Fluidic VGs: mass-flow rate effect

⟨ = 3.5°

- Fluidic VGs are effective for very low values of the mass-flux (2g/s)

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y/b=70%-1.5

-1

-0.5

0

0.5

1

0 10 20 30 40 50 60 70 80 90 100

x/c(%)

-Kp

Baseline

all active 2.4g/s(Cmu=2.8e-4)

1VG/2 active 2.2g/s(Cmu=2.5e-4)

1VG/3 active 2.1g/s(Cmu=2.4e-4)

1VG/4 active 0.9g/s(Cmu=1e-4)

1VG/5 active 0.7g/s(Cmu=8.1e-5)

1VG/6 active 1g/s(Cmu=1.1e-4)

1VG/7 active 0.8g/s(Cmu=9.2e-5)

• Fluidic VGs: spacing effect

⟨ = 3.5°

JTI-SFWA 1.1.2 : S3Ch Wind Tunnel Tests

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• Fluidic VGs: spanwise location effect

⟨ = 3.5° y/b=70%

-1.5

-1

-0.5

0

0.5

1

0 10 20 30 40 50 60 70 80 90 100

x/c(%)

-Kp

Baseline

VG 1 to 7 1.3g/s(Cmu=1.5e-4)

VG 8 to 13 0.9g/s(Cmu=1e-4)

VG 14 to 19 1g/s(Cmu=1.1e-4)

VG 20 to 25 1.1g/s(Cmu=1.3e-4)

JTI-SFWA 1.1.2 : S3Ch Wind Tunnel Tests

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Unsteady measurements: comparison of mechanical and fluidic VGs effects

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• Decrease of the RMS level on the pressure and on the accelerometers • Nearly same effect between passive and active VGs

Mechanical VGs => BAY model in elsA

elsA RANS computation of the S3Ch model with passive VGs

M = 0.82, α = 3,5o (buffet for α>3,0o)

ReAMC = 2,8 106

Exp.

Good agreement between CFD results and experimental data if the mesh is fine enough to discretize each vortex

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Exp.

Fluidic VGs => Overset grid method

Good agreement between CFD results and experimental data

elsA RANS computation of the S3Ch model with fluidic VGs

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Peniche / Fuselage / Wing Wing cross-section:

OAT15A airfoil Wing span: 1.225m Chord length:

0.450m 0.225m ϕ=30°

ONERA S2MA WT

S2MA WTT

Devices tested: Baseline Configuration Mechanical VGs Fluidic VGs (continuous flow rate) Fluidic TED (continuous flow rate) designed with PPRIME

ONERA Half-model

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Baseline (α=4.25°) Mechanical VGs (α=3.5°)

Fluidic VGs (α=4.25° - Cµ=0.06%)

S2MA WTT: comparison between passive and fluidic VGs

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- Effect of Fluidic VG at Cµ=4.6 10-5 (3g/s) comparable to Mech. VG - Saturation efficiency on CL for Fluidic VGs at Cµ higher than 9.2 10-5

- BUT still efficient on decreasing unsteadiness (Kulites transducers)

Fluidic VGs configuration

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Fluidic VGs configuration

Lift gain maximum for a spanwise spacing of 46d

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Pulsed Fluidic VGs configuration

- Low pass filter behaviour of the shock oscillation - Frequency bandwidth of the shock around 160Hz

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Fluidic TED at Cμ=0.0027

M=0,82 Pi=0,6b

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0,2

0,4

0,6

0,8

1

-2 -1 0 1 2 3 4 5 6 7

Alpha (°)

Cz

Baseline (192)FTED Cmu=0,0090 (472)FTED Cmu=0,0058 (474)FTED Cmu=0,0036 (475)FTED Cmu=0,0027 (477)Baseline (193)

Fluidic TED vs. Baseline Configuration

Mech. TED deflected at 30°

Fluidic TED configuration

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Comparisons at iso-CL

Fluidic TED configuration

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- Mechanical/Fluidic VGs delay buffet onset by 0.3° and 1° respectively - Fluidic TED delay buffet onset only in CL

Results summary

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- Mechanical/Fluidic VGs delay buffet onset both in the (M,α) and (M,CL) planes - Fluidic TED delay buffet onset only in the (M,CL) plane For more details see: “Buffet Characterization and Control for Turbulent Wings”,

Aerospace Lab, Vol. 6, 2013. http://www.aerospacelab-journal.org Next presentation: closed-loop buffet control by A. Lepage

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Results summary