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  • Turbulence and AeroacousticsResearch team of the Centre Acoustiquecole Centrale de Lyon & LMFA UMR CNRS 5509

    SMI - Turbulence en mcanique des fluides, Acadmie des Sciences, 14 juin 2011

    Mcanique des fluides, transferts et

    rayonnement sonore

    Christophe Bailly & Christophe BogeyUniversit de Lyon, Ecole Centrale de Lyon & LMFA - UMR CNRS 5509

    Institut universitaire de France

    http://acoustique.ec-lyon.fr

    1

    http://acoustique.ec-lyon.fr

  • x Acknowledgments q

    Olivier Marsden (ECL, Assitant Prof.)Thomas Castelain (ECL, Assitant Prof.)Sbastien Barr (Dassault-Aviation)Julien Berland (EDF)Vincent Fleury (ONERA)Benot Andr (ECL, Ph.D. Student)

    2 Acadmie des Sciences, 14 juin 2011 Christophe Bailly & Christophe Bogey

  • x Outline of the talk q

    Motivations

    Example of aeronautics, commercial air transport & military applications

    Predicting jet mixing noise

    Scales and control parameters Large-eddy simulation (LES) and direct noise computation (DNC) Role of coherent structures Mixing and noise of turbulent subsonic jets Introduction to underexpanded supersonic screeching jets

    Concluding remarks

    3 Acadmie des Sciences, 14 juin 2011 Christophe Bailly & Christophe Bogey

  • x Motivations q

    Physics-based predictions for real jets, i.e. dual, hot, with co-flow, shock-cellsand noise reduction devices : shape optimization, variable geometry chevrons orfluidic actuators

    High-bypass-ratio nozzle (cfm56 type)chevrons on the fan and core nozzles

    (Loheac et al., SNECMA, 2004)

    QTD2 - Boeing - NASAAIAA Paper 2006-2720

    Castelain et al.AIAA Journal, 2008, 45(5)

    understanding of noise generationmechanismsproviding reliable predictionsgiving insight for noise reduction

    Lobed exhaust ejector/mixer systemCFM56-5C engine powering Airbus A340

    4 Acadmie des Sciences, 14 juin 2011 Christophe Bailly & Christophe Bogey

  • x Motivations q

    Supersonic jets

    Ariane V ECA - CNESflight 185 - 41st launch V - 2008

    acoustic environment of space launchers at lift-off and protection of payloadsmilitary aircrafts (e.g. hearing protection of navalcrew on aircraft carrier deck)broadband shock-associated noise in cruiseconditions : cabin noise

    Pratt & Whitney FX631jet engine (F-35 JointStrike Fighter)http://www.jsf.mil

    Kleine & Settles,Shock Waves (2008)

    Take off from aircraft carrier(noise levels exceed 140 dB)

    5 Acadmie des Sciences, 14 juin 2011 Christophe Bailly & Christophe Bogey

    http://www.jsf.mil

  • x Motivations q

    Economic and societal impacts

    Noise levels (EPNdb, sideline), no normalization

    1960 1970 1980 1990 2000 201085

    90

    95

    100

    105

    110

    115

    120

    A300

    A300600

    A319 A320200 A321200

    A330300 A340300

    A340600

    B707

    B720

    B727100

    B737200

    B747100

    B747400

    B767200 B777200

    Falcon 900

    F28

    F100

    GIV GV

    DC8 DC10

    MD80

    Comet 4

    BAe 146

    Trident 1

    Caravelle 10

    ERJ 145

    ATR42

    ATR72

    L1011

    VC10

    year of entry into service

    EPNdB (sideline)

    3rd generationturbofan

    turbojet

    2nd generationturbofan

    1st generationturbofan

    A380

    Advisory Council for Aero-nautics Research in Europe(ACARE 2000 2020) ; Traf-fic growth must be compensa-ted for by quieter aircrafts

    Jet noise during take-off re-mains the major component oftotal aircraft community noise(between a third and half ofthe energy)

    Sound insulation tax, France(TNSA) 50 M/year

    6 Acadmie des Sciences, 14 juin 2011 Christophe Bailly & Christophe Bogey

  • x Subsonic turbulent jets q

    Aeroacoustic scaling

    Acoustic Mach number Ma

    Ma =ujc

    noise Mna

    Strouhal number St

    St = fDuj= fuj/D

    non-dimension frequency

    Reynolds number ReD

    ReD =ujD =

    D2/D/uj

    viscous timeconvective time

    Duj

    nozzle

    7 Acadmie des Sciences, 14 juin 2011 Christophe Bailly & Christophe Bogey

  • x Subsonic turbulent jets q

    Reynolds number ReD = ujD/

    Prasad & Sreenivasan (1989)ReD 4000

    Dimotakis et al. (1983)ReD 10

    4

    Kurima, Kasagi & Hirata (1983)ReD 5.6 10

    3

    Ayrault, Balint & Schon (1981)ReD 1.1 10

    4

    Mollo-Christensen (1963)ReD = 4.6 10

    5

    8 Acadmie des Sciences, 14 juin 2011 Christophe Bailly & Christophe Bogey

  • x Subsonic turbulent jets q

    Initial conditions at the nozzle exit

    Kolpin, J. Fluid Mech. (1964)Mollo-Christensen, Kolpin & Martucelli, J. Fluid Mech. (1964)

    ReD = 0.85 105 ReD = 1.82 10

    5 ReD = 5.24 105 ReD = 6.85 10

    5

    Transition region moves from the mixing layer to thenozzle boundary layer as ReD

    9 Acadmie des Sciences, 14 juin 2011 Christophe Bailly & Christophe Bogey

  • x Subsonic turbulent jets q

    Disparity of scales

    Isothermal jet, a/

    ReD/(Ma St) (ReD = 106, Ma = 0.9, r/D 10)

    Mollo-Christensen (1963), ReD = 4.6 105

    D

    uj xc

    laminar potentialcore length xc

    u p

    a

    ua pa

    a/ 103u/uj 0.16

    ua/u 104

    pa/p 103

    p2a

    =90o

    M7.5a

    10 Acadmie des Sciences, 14 juin 2011 Christophe Bailly & Christophe Bogey

  • x Direct computation of aerodynamic noise q

    High fidelity flow/noise simulation in a physically and numerically

    controlled environment

    artificial turbulentstate at nozzle exit

    to mimic turbulent BLReD, Re , ue/uj

    non-reflectingboundary conditions

    & WEM

    an error of 1% onthe aerodynamic

    pressure fieldyields an errorof 100% on theacoustic field !

    Barr et al., Int. J. AeroAcous. (2006)Bogey & Bailly, J. Fluid Mech. (2007)

    fluctuating pressure fieldp outside of the flow

    vorticity in the flow

    11 Acadmie des Sciences, 14 juin 2011 Christophe Bailly & Christophe Bogey

  • x Subsonic turbulent jets q

    First Direct Noise Computation (DNC) of a subsonic round jet

    Freund, J. Fluid Mech. (2001), ReD = 3600 & M = 0.9see also Colonius, J. Fluid Mech. (1997)

    Kurima, Kasagi & Hirata (1983)ReD 5.6 103

    nx nr n = 640 250 160 29 106 pts/r0 0.02small random perturbation to seedthe instabilities and turbulence

    12 Acadmie des Sciences, 14 juin 2011 Christophe Bailly & Christophe Bogey

  • x Subsonic turbulent jets q

    Direct Numerical Simulation M = 0.9 & ReD = 11000

    4

    16

    vorticity norm in the plane z = 0full jet in top view 0 x 27.5r0

    (116 pts bottom figure)

    NEC SX-8 cluster at HLRS center in Stuttgart, Germany212 GFlops, 250 GB of memory, 30,000 CPU hours

    nx ny nz = 2010 613 613 755 106 ptskc 1.5 kc grid cut-off wavenumberx = y = z = r0/68simulation time T = 3000r0/uj , 295,000 iterations = 0.01 r0

    Bogey & Marsden in Advances in Parallel Computing, 19, 2009see also Bogey & Bailly, J. Fluid Mech., 629, 2009

    13 Acadmie des Sciences, 14 juin 2011 Christophe Bailly & Christophe Bogey

  • x Large Eddy Simulation of turbulent jets q

    Energy budget across a self-preserving jet M = 0.9 & ReD = 11000

    nx ny nz = 651 261 261 = 44 106 pts2.8 106 time steps Nec SX-5/8 104 h CPU

    Expts of Panchapakesan & Lumley (1993) Self-similarity region for 120r0 x 150r0 All the terms are explicitly calculated including the

    filtering dissipation, to check the sum.

    vorticity norm in the plane z = 0 0 0.5 1 1.5 20.03

    0.02

    0.01

    0

    0.01

    0.02

    0.03

    y/0.5

    (normalized by cu3c0.5)

    mean flow convection

    production

    dissipation

    turbulence diffusion

    pressure diffusion

    expt. data of P. & L. (1993)

    14 Acadmie des Sciences, 14 juin 2011 Christophe Bailly & Christophe Bogey

  • x Large Eddy Simulation of turbulent jets q

    Energy budget across a self-preserving jet M = 0.9 & ReD = 11000

    Interpretation of Panchapakesan & Lumley (J. Fluid Mech., 1993) versusHussein, Capp & George (J. Fluid Mech., 1994)

    P. & L. H.C. & G.

    0 0.5 1 1.5 2

    0.03

    0.02

    0.01

    0

    0.01

    0.02

    0.03

    y/0.5

    0 0.5 1 1.5 2

    0.03

    0.02

    0.01

    0

    0.01

    0.02

    0.03

    y/0.5

    in agreement with P. & L. who neglected presssure diffusion and not with H.C.& G. who used turbulence modelling for dissipation

    Bogey & Bailly, J. Fluid Mech. (2009)

    15 Acadmie des Sciences, 14 juin 2011 Christophe Bailly & Christophe Bogey

  • x Large eddy simulation q

    Closure : subgrid-scale model e.g. Sagaut (2006), Lesieur (2007)

    Projection modeling by a spacial convolution filtering u = G utu + (uu) + (p/) + 2u = sgs

    structural approach, find a model for the sgs stress tensorfunctional approach, surrogate the mean action turbulent kinetic energy balance is more important turbulent kinetic energy cascade is dominant dissipation

    Two main classes of methods in physical space

    turbulent eddy viscosity modelshyperviscosity ( sgs h2n) or high-order explicit filtering

    Pruett et al. Domaradzki, Adams et al. Visbal, Gaitonde, Rizzetta ADM ...

    LES - Relaxation filtering sgs = G u

    Berland et al., J

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