Interaction fluide structure dans un faisceau de tubes :
physique et modlisation M. Braza, G. Harran, G. Barbut, Y. Hoarau
Journe Thmatique GDR Interaction Fluide-Structure, 4/12/07 EDF-
Chatou
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2 Phnomnes physiques capter par lapproche de macrosimulation :
Instabilits de basse frquence bien distinctes par rapport la
turbulence alatoire Flottement hydrolastique Prdiction des
chargements proche-paroi: couplage d lchange nergtique :
fluide-structure
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3 Longitudinal vortices along the span in connexion with the
von Karman ones THE IMFTs CIRCULAR CYLINDER - DESIDER EU program
TEST-CASE In S1 Wind tunnel IMFT : SIMULTANEOUS 3C-PIV and
Time-resolved PIV Re=140,000 IUTAM Symposium Unsteady Separated
Fmows and their Control, June 2007 and J. Fluids& Structures,
in print
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4
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5 Vertical velocity spectrum in a cylinder wake, Re=140 000
Experimental data from PIV (M. Braza,R. Perrin, Y. Hoarau, Journal
of Fluids and Structure 2006) and LDV (Djeridi et al, JFTAC 2003)
Spectrum from originals signals Spectrum from phase-averaged
signals The macrosimulation approach to capture the organised
coherent motion and the random turbulence
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OES : Schematic separation of coherent/random turbulence parts
in the spectral domain In the physical domain: phase average
decomposition: Part (1): to be resolved Part (2): to be modelled by
reconsidered statistical turbulence modelling, efficient in high-Re
unsteady wall flows (Dervieux, Braza, Dussauge, Notes on Num. Fluid
Mech., 1998, Vol. 65, Braza, Perrin, Hoarau, J. Fluids &
Struct., 2006, Vol. 22 OES : Organised Eddy Simulation
Macrosimulation
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The phase-averaged turbulence stresses: Evaluated by tensorial
eddy-viscosity concept Derived from second-order modelling
Bourguet, Braza, Perrin, Harran, AIAA J., 45, 2007. / t + / x j + /
x j Temporal non-linear convection new turbulent stresses =- /dx i
+ / x j
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8 Anisotropic OES modelling Considerations from the IMFT
circular cylinder exp. study DESIDER EU program, Perrin et al, Exp.
in Fluids, 42, 2006 Re=140,000 Bourguet et al, AIAA J, 45,
2007
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9
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10 Anisotropic OES Modelling: Tensorial eddy-viscosity concept
* Directional C i coefficient, a jk : Turbulence stress anisotropy,
S ij = Strain-rate tensor, advectable directional criterion derived
from DRSM Sarkar, Gatski, Speziale transport eqns, JFM 227 *
Bourguet, Braza, Perrin, Harran, AIAAJ. 45, 2007 C i = C vi /k
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12 Good agreement of experimental and modeled anisotropy tensor
Implementation into NSMB solver PhD R. Bourguet Anisotropic OES
modelling
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13 Comparison of the experimental and predicted phase-averaged
turbulence shear-stress Bourguet, Braza, Perrin, Harran, AIAAJ,
Vol.45,N5, 2007
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14 Yields simplified isotropic OES in agreement with our
previous studies derived by DRSM (Hoarau, Braza, IUTAM-02 Symposium
Procs, Unsteady Separated Flows) Anisotropic OES modelling
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15 Flow around a NACA 0021 airfoil at 60 angle of attack OES
approach and two-equation modelling (isotropic version) *Use of the
modified damping function (Jin & Braza, AIAA J. 1994) derived
from DNS *use of the eddy-diffusion coefficient adapted by OES/DRSM
C =0.02
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16 Fig. 4c. Up: Iso-U velocity averaged field compared with the
PIV data, down, phase-averaged experimental field at phase- angle
225 compared with the DES-k-omega (IMFT). PIV -3C Moyenne de phase
OES/k- OES
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17 3D structure of shear-layer instability OES approach: allows
simulation of 3D shear-layer instability at high-Re Q_criterion
Re=140,000
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18 Interaction fluide-structure Faisceau de tubes
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19 Petit Nombre de Scruton Instabilit domine par lamortissement
Implique un seule degr de libert (SDOF). Grand nombre de Scruton
Instabilit domin par la raideur Implique deux degrs de libert.
Variation de la vitesse critique en fonction du paramtre masse-
amortissement (S. J. Price, M.P. Paidoussis, J. Fluids &
Struct., Vol. 22, 2006)
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20 Modlisation linaire des forces fluide- lastiques x y U k c
kc Equation dynamique du cylindre SDOF Modle de force
fluide-lastique Connors (1970) quasi-statique Price,Padoussis
(1986) processus amnsique Granger Padoussis (1996) processus mmoire
Re = 20000
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21 Application linteraction fluide-structure dans un faisceau
de tubes Code NSMB Navier-Stokes Multiblock Consortium: EPFL, CFS
Engn, KTH, ETHZ, Tech. Univ. Mnich, IMFT, IMFSS, RUAG Aero Prsente
application Approche ALE Schmas centrs Prcision au second-ordre
temporel et spatial Modlisation OES modles deux quations, de type
k- 41616 cellules
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22 Faisceau de tubes configuration statique Re=20 000
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23
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24 Configuration statique
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25 Variation des coefficients de trane et de portance en
fonction du temps (Ur=1.18) Analyse spectrale du coefficient de la
portance frquence doscillation du cylindre frquence du dtachement
tourbillonnaire Avec oscillation verticale du cylindre du milieu la
frquence naturelle et amplitude 0.1D
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26 Cylindre du milieu en vibration libre
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27 III. Configuration tudie Dtail du maillage Domaine du calcul
P/D=1.75 144 blocs - 73728 cellules
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28 Variation des coefficients de trane et de portance en
fonction du temps Analyse spectrale du coefficient de la portance
entre les instants t=83.06 s et t=301.6 s. f 0.21 Hz
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29 Conclusion Interaction fluide-structure faisceau de tubes
Approche OES : Evaluation des charges paritales - change nergtique
fluide-structure Dissociation parties organise et interaction avec
turbulence alatoire Approche 2D ( mthode non-intrinsque 3D )
Capacit de prdicition plus haut Re
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30 Perspectives Dveloppements actuels: Prdiction faisceau de
tubes avec A_OES Prdiction en 3D Analyse de linstabilit de
flottement cylindres en tandem Exprience physique avec
TR-PIV/3C-PIV