Fluid id-Stru ructure re I Intera raction on i in STAR-CC CCM+ Alan M Muelle ller CD CD-ada adapc pco
What at is F is FSI SI? Air Interac action wit ith a a Flexible Struc uctur ture
What at is F is FSI SI? Water/Air I Interac actio ion with a a Structure Courtesy CFD Marine Courtesy Germanischer Lloyd
What at is F is FSI SI? Vortex Induced V Vib ibrat ation an and Gal allo loping
What at is F is FSI SI? Aeroelas astic F Flutter
What at is F is FSI SI? Hyd Hydroplan aning
What at is F is FSI SI? Gulp ulping ng Courtesy Tetra Pak
What at is F is FSI SI? Ask 20 en engi gineers “What is FSI SI?” and d you will likely ge get 2 20 di different answers There is not simply one ap approac ach v valid alid for al all FSI problems The an anal alyst must be presented wit ith a a ran ange of options an and chose the most suitab able le
The U Uniq ique Ch Chal allenges o of FSI SI Sim Simulations Protocols a and format ats f for exchan anging data – Getting data from Code A to Code B Map Mappin ing dat ata a between n non-conforma mal m mes eshes es – Finding neighbors and interpolating Coupling methods – Algorithms for accuracy, stability, efficiency Dynam amic ic fluid mesh evolu lutio ion – Topology changes in the fluid domain Valid alidat ation of F FSI r result lts 9
Enabli ling t techn hnolog ologies t to m meet t the c challe lenges VOF f for or fre free s surface t tra ransient flo flow Overs rset mesh shes f s for m motio ion an and d deformat matio ion Fluid i id interactio ion wit with – multi-body rigid structures – compliant structures Co-Simula Co lation b between d differe rent C CAE c codes Mappi apping b between n non-conformal mal m mesh shes Para ralle llel s l scalabili lity o on compute c cluster
Simu mulat atio ion o of Store S Separ arat atio ion DFBI – Fluid interac action wit ith a a Rig Rigid id B Body Over erset Tec echnology
Simu mulat atio ion o of Lifeboat at L Launchin ing VOF OF for f free s surfac ace tran ansient flo low DFBI – Fluid interac action wit ith a a Rig Rigid id B Body Over erset Tec echnology Overset grids allow simulation of launching of various devices (lifeboats, missiles etc.).
Th The Ch Challenges o of FSI MAPPIN PPING
The he 3 3 st steps ps of “ of “Ma Mapping” Sea earch ching f for op opposing nei neighbo bors – Most of the computer time Interpola olating s source s stencil d l data on on a target p point – Source and targets may be face or vertex Often r en requi uires es i int nteg egration ( (quadratu ture res) – intensive extensive variables – pressure force – heat flux heat – FEA nodal loads: integration of intensive variables against the shape function.
Neighb hbor S or Search I h Impera rative Sear arch r requir ires l lit ittle user in intervention The search e excludes potential al neighbors based on proximity y and o orientat atio ion Critic ically y importan ant for s sheet metal al parts – resolve ambiguities of poor geometry – thin solid parts may be on the wrong side of the fluid surface Par aral alle lel Map Mappin ing is is a a must! – Takes advantage of distributed memory Courtesy of Daimler
Mappi apping D Disp isplac acement f for Low Y w Y+ me meshes C 0 continuous mapping very important for low y+ meshes Otherwise very easy for morpher to invert high aspect ratio cells in prism layer
Inconsist sistent G Geome metric ic R Repr prese sentat atio ions FEA VIEW of a WING Beam elements Kinematic Couples ? Shells(no mass,stiffness) Beam to Surface Mapping CFD VIEW of a WING
Th The Ch Challenges o of FSI DATA E A EXCH CHANG ANGE 18 18
Metho hods f for E Excha hanging Data S STA TAR-CC CCM+/CA CAE File B Based T d Transf sfer: I Import/Map/E ap/Expo xport – Data exchange via files on a hard-disk – CAE code need not be resident in memory – Often called “Loose Coupling” – User responsible for exchange synchronization So Socket Base Based T Transfer: Co Co-Sim Simulat atio ion A API – API controls exchange synchronization – Data exchanged via sockets – CAE code and STAR-CCM+ both executing in memory • STAR-CCM+ to STAR-CCM+ Co-simulation • STAR-CCM+ to 1D external Codes – GT Power, Wave, Olga, AMESim, Relap5 • STAR-CCM+ to Abaqus Co-Simulation using Abaqus API
STA TAR-CCM+ : : Loosely Co Coupl pled CA CAE Su Suppo pport Import CAE CAE Me Mesh: h: import from/export to the native CAE format – Abaqus, Nastran, Ansys, STAR-CCM+ – RadTherm, es-ice Map & Expor ort R Resu sults t s to o CAE – Surface Loads • Pressure, Shear Traction • Heat flux or Temperature • Heat Transfer Coeff, Ambient Temp – Volume Loads • Temperature Display mapped results on imported mesh • Heat Source Import & Im & Map ap FE FEA R Res esul ults – Temperature Fluid Wall BC – Displacement, Eigenmodes Morpher
Heeds: W : Work rkflo low P Process C Control ol STA TAR-CCM+ can an p provide an an im import/map ap/export servic ice as as a a powerful complement nt to HEED EEDS
Abaqus/STAR-CCM CCM+ C Co-Simula lation Co Coupling v via ia Ab Abaqu qus Co Co-Sim Simulat atio ion A API o of SIMULIA – Manages Coupling Synchronization/Exchange/Mapping – Abaqus v6.13/STAR-CCM+ v8.04+ (implicit coupling) – Surface to Surface Mapping STA TAR-CCM CM+ A Abaqus s (expl xplic icit it or stan andar dard) d) Hydroplaning – Pressure – Shear traction Overset – Surface HTC, Tref Ab Abaqu qus STA TAR-CCM CCM+ – Displacement, velocity – Temperature 22 22 Ball and Socket Stop Valve
Flexible le r riser ( r (L/D = = 50) in turb rbule lent crossflo flow. Strateg egy : : Coup uple S STAR-CCM CCM+ to Abaqus – Implicit Coupled on workstation STAR-CCM+ V Vor ortex Induced F Flo low a arou ound Fle lexible le P Pipe Aba baqus F FEA EA for or Flexibl ble e Pi Pipe Riser er di dimen ension ons: Riser cross sec ection L = 3.8125 m, D = 76.25 mm T = 7.05 mm Current ent: Vin = 1.2 m/s Re(D) = 81700 Struc uctur ural al Material al P Proper perties es: Young’s Modulus= 1.5 GPa; Poisson ratio = 0.42; density = 8563 kg/m 3 ;
Co Coupled So d Solution : : Disp isplac acement an and d Vortic icit ity z/L=0. 0.25 25 z/L /L=0.5 .5
The C Challe llenges of F FSI Co Coup uplin ing T g Tech echniq nique
Degre rees o of Coupli ling Two-way ay coupl pling for or f fluid-ela lastic e c equilibrium – Steady-state flow over static structure deformed by fluid loads One ne-way dy dynamic c c coupl pling – Loads only go from fluid to structure – Loads only go from structure to fluid Two-way dy dynamic c coupli pling – Explicit (exchange loads once per time step) • Unstable for relatively light and/or compliant structure interacting with heavy, incompressible fluid • Interest in physics with time scales which are long compared to acoustic time scales – Implicit (exchange loads more than once per time step)
Th The Ch Challenges o of FSI Val alid idat atio ions
Exp xperimental V Val alid idation: W Wedg dge D Drop I p In Wat ater Comparison of E Experime ments and d Model dels Pet eter erson, Wyma man, and Frank: “ “ Dr Drop Tes ests t to Su Support W Water-Impac act an and Pl Planing Boat D Dynami mics Theo eory ”, ”, D Dahlgr gren en Division N Naval Surface e Warfare e Cen enter, C CSS/ SS/TR-97/25 STA TAR-CCM+ VOF with differen ent bodi dies es – Rigid Body (6DOF, DFBI) – Elastic Body (FV stress) – Elastic Body (Abaqus Co-Simulation) – Elastic Body (FE Stress)
Wedg dge D Drop I p In Wat ater Vertical acceleration All Methods give good agreement to experiments Equivalent Stress (MPa) Angular acceleration (rad/s 2 )
AeroElast astic ic Predic dictio ion Work rksho hop: H : HIRENASD 53K 53K nod nodes 2. 2.3M 3M cel ells
Aerodynamic amic E Equil ilib ibriu ium m at d different A AOA St Static St Structure, St Stead ady air airflow at w at de deformed sh shape ape =0.48x10 -6 Ma=0. =0.8, 8, R Re=23. e=23.5x10 6 , q/ q/E=0. Lift Coefficient Wing Tip Displacement
Wi Wind ndoff Vibrat atio ion M Modes : s : Ab Abaqu qus vs vs Experi riment f=25. 5.55 55 Hz (26. 6.25 25) f=106. 06.20 20 Hz f=80. 0.25 25 Hz (78. 8.20 20) f=160. 60.35 35 Hz (165 65.25 25)
Aeroelastic Equilibrium Cp: AOA 2 ° ST STAR AR-CCM CM+/Abaqu baqus NASA ASA FUN3D
ium Cp: AOA 2 ° , near wing tip Aer eroe oelas astic Equilib ilibriu x/ x/c ST STAR AR-CCM CM+/Abaqu baqus NASA ASA FUN3D
Fluid id-Elast astic ic I Inst stab abil ilit ities i s in a Tube B Bundle Weaver & & Ab Abd-Rabbo bbo. A A Flow V Visu sual aliz izat atio ion S Study o of a Squar are Arr rray of y of Tubes i in Water Crossflo flow. J Journal al o of Fluids ids Engineeri ring. S . September 1 r 1985. Vol. 1 . 107, p p. 354-363 363.
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