BBVF Meneghini

Review of fundamentals Vortex-induced vibration Interference problem Aeroacoustic Concluding Remarks Acknowledgments

Vortex-induced issues:from vibration to noise generation

Julio R. [email protected]

NDF - Fluids and Dynamics Research Group, POLIUniversity of Sao Paulo - Brazil

Workshop:From fast cars to slow flows over bluff bodies

Translating knowledge on separated fluid mechanics2009 Imperial College London

University of Sao Paulo, Brazil Julio R. Meneghini 1 / 43

mailto:[email protected]


Outline

1 Review of fundamentalsVortex shedding and vortex-induced vibration issuesVortex-induced noise

2 Vortex-induced vibrationVIV on marine risersBack to fundamentals

3 Interference problem3d simulationsBack to fundamentals

4 AeroacousticSound generated by the flow around a circular cylinderFlow around a slatBack to fundamentals

5 Concluding Remarks6 Acknowledgments



Outline








Vortex shedding and vortex-induced vibration issues

Vortex shedding from bluff bodies

Two and three-dimensional flowStrouhal number versus Reynolds number curveCorrelation length experiments (Szepessy & Bearman 1992),wavy blunt trailing edge experiment (Tombazis & Bearman 1997)Onset of three-dimensionalities:

Secondary instabilitiesThree-dimensional modes (Williamson 1992, Leweke & Provansal1995): Mode A, Mode B (and later Mode QP, by Blackburn et al.)Clrms crisis (Norberg 2002)




St x Rey curve: Mode A and Mode B, Williamson (1992), Leweke & Provansal (1995)




Mode A: simulations by Siqueira (1999) and experiments by Williamson (1992)




Mode B: simulations by Siqueira (1999) and experiments by Williamson (1992)




Wavy blunt trailing edge experiments by Tombazis & Bearman (1997)




Vortex shedding from bluff bodies

Vortex shedding from an oscillating bluff body

Lock-in boundary:Experiments at high Re by Koopman (1968)Low Re calculations by Meneghini & Bearman (1995), employingVIC (Graham 1989)

Modes map (Williamson & Roshko 1988):Mode 2SMode P+S and 2P

Phase angle, its relation to energy transfer and shedding timing(Griffin 1980, Bearman 1984, Ongoren & Rockwell 1988)Oscillation effect on three-dimensional modes A and B




Williamson & Roshko (1988) Map




Mode P+S: Meneghini & Bearman (1995) and Williamson & Govardhan (2004)




Interference effect

Two circular cylinders side-by-side

Force time histories (Bearman & Wadcock 1973)Synchronization of the wake, flip-flop regime (experiments byWilliamson 1985)Chaotic state (2d calculations by Meneghini et al. 2001)

Two circular cylinders in tandem

Drag inversion on downstream cylinder (Williamson 1985,Meneghini et al. 2001)Three-dimensional modes (Carmo & Meneghini 2006, Carmo etal. 2009)




Interference regimes: Carmo & Meneghini (2006) and Carmo et al. (2009)

Regime SG

Regime AG

Regime WG




Interference effect on VIV

Two circular cylinders in tandem, one free to oscillate

VIV and WIV regimes (Assi et al 2006, and Assi et al. 20??)In WIV regime, VIV supressores (e.g. strakes) may looseefficiency (Korkischko & Meneghini 2009)




VIV and WIV: Assi et al. 2006




VIV and WIV, straked cylinder: Korkischko & Meneghini (2009)



Vortex-induced noise

Aeroacoustic

Lighthill analogy

Bluff bodies: circular cylinderHigh lift devices: slat and flapFfwocs Williams and Hawkings’ equation



Outline








VIV on marine risers

Fatigue analysis of risers immersed in complex flowfields

Vortex method and FEMLagrangean vortex method (Spalart 1989 with few changes inthe algorithm)Finite element method for dynamic response (Ferrari 1998 andMourelle 2000)We must take care with:

Number of strips along the riser (at least 10 per wave length)Number of simulated cycles for fatigue analysisExamples




VIV in a steel catenary riser, Meneghini at al. (2007, Report VIV P55, FUSP-BR)




Experiments in Delft: Chaplin et al. (2005)



Back to fundamentals


Oscillating cylinder and secondary instabilities

Floquet analysis (Gioria et al. 2009)3d DNS simulations (Spectral Element Method)Revised lock-in boundaryTransient growth analysis




Three-dimensional simulations (SEM-Fourier), oscillating cylinder: Gioria (2009)

1) A/D = 0.4 and f/fs = 0.95:

2) A/D = 1 and f/fs = 0.95:




Floquet analysis, oscillating cylinder: Gioria et al. (2006) and Gioria (2009)

1) A/D = 0.4 and f/fs = 0.95:

2) A/D = 1 and f/fs = 0.95:



Outline








3d simulations

Interference regimes: Carmo 2005

Re = 270, l/d=1.5 (Re = 270, l/d=3)




Floquet analysis: secondary instability, Carmo et al. 2008, Carmo et al. 2009,

Regime SG, Lx/D = 1.5, Recr = 315 and Lz/D = 2.096





Regime AG, Lx/D = 1.8, Recr = 409 and Lz/D = 2.838





Regime AG, Lx/D = 2.3, Recr = 250 and Lz/D = 4.6



Outline








Sound generated by the flow around a circular cylinder

Flow around a circular cylinder, Re = 90000, LES, Fluent-Ansys



Sound generated by the flow around a circular cylinder

Flow around a circular cylinder, Re = 90000, LES, Fluent-Ansys, SPL at 120d



Flow around a slat

Slat simulation: Ma=0.1, Re = 1.2M, URANS (Spalart Almaras), Bonatto 2009




Floquet analysis of the flow around a NACA0012 airfoil, Tsiloufas et al. 2009

1,0

|μ|

Re 400 Re 450 Re 460 Re 470 Re 500 Re 550

0,0

0 5 10 15 20

|μ|

β∙c

0,5

0,6

0,7

0,8

0,9

1,0

λ/c

0,0

0,1

0,2

0,3

0,4

0,5

440 460 480 500 520 540 560

λ/c

Re




Floquet analysis of the flow around a NACA0012 airfoil, Tsiloufas et al. 2009



Outline








Stability analysis studies: they can provide very importantinformation regarding the physical mechanism of VIV and VINStability analysis studies: they can give clever insights regardinghow to properly carry out CFD simulationsFlow control strategies based on stability analysis are alreadyfeasibleThe need for the development of high order CFD schemes forincompressible and compressible flowsWe still have a very long way to be able to precisely calculateVIV and VIN with a level of detail needed for the oil andaeronautical applications



Outline








Acknowledgments

For all their achievements and source of motivationPeter Bearman and Mike Graham

For all collaboration and work going onSpencer Sherwin, John Chaplin, Richard Willden, Amie Morgans,Charles Williamson, Thomas Leweke, Theofillis Vassilis

Bruno Carmo, Gustavo Assi, Erico Santos

Fábio Saltara, J.A.P. Aranha, Cesario Siqueira, Ricardo Flatschart,Cássio Yamamoto, Rodrigo Fregonesi, Adson Paula, Paulo Jabardo,Iago Barbeiro, Alessandro Lima, José Lopez, Rafael Gioria, IvanKorkischko, Guilherme Franzini

For the creation of an enjoyable working environment at ICNikolas Tombazis, Stefan Szepessy, Richard Arkell, Gray Moita



Acknowledgments

Sponsors

Fapesp, Finep, CNPq, CapesPetrobras, Embraer, Voith/Siemens, Oxiteno, BP


BBVF Meneghini

Documents

Transcript of BBVF Meneghini