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NUMERICAL MODELLING OF MECHANICAL COUPLING IN FLUIDS & STRUCTURES SOFTWARE fluidyn - MP PRESENTATION OF fluidyn - MP General : role & utility of Computational Fluid Dynamics A reliable numerical representation of a real processus with the help of well adapted physical models Easy to use & adapted to optimisation studies in industrial processes Economic with a security advantage Ideal complementary tool for experimental measurements Access to physical variables (velocities, temperature, etc.) at each point in the domain pressure, Software fluidyn - MP, FSI model Strong coupling & conjugate heat transfer between fluid & structures integrated in a single software platform Robust physical models & various well adapted solvers Finite Volume Method for fluids and Finte elements method for structures Automatic exchange of boundary conditions between fluids & structures - Adaptative Fluid Mesh Local time step used to reduce CPU time Fluid Solver Solution of Navier-Stokes Equations 3-Dimensions Compressible / incompressible Mechanical / thermal shocks Viscous / non-viscous Laminar / turbulent Multi-species Multi-phase Fluid Solver Non-Newtonian Flows : Bingham law Power law Chemical – combustion reactions Arrhenius model Eddy-break-up model Eddy dissipation model Deflagration & fire BLEVE Pool fire Detonation JWL model Two phase flows droplets, bubbles, particles Euler-Lagrange Monte-Carlo, Free surface flow ( VOF method + CSF method) Fluid Solver Free surface two phase flows VOF method (Volume of Fluid) Finite volumes solution Adapted to gravity controlled flows whose interfaces undergo large deformations 3 high order convective schemes (Inter-Gamma Differencing, HRIC & CICSAM) CSF method (Continuum Surface Force) for modelling surface tension Fluid Solver Free surface two phase flows ALE method (Arbitrary Lagrangian Eulerian) Finite volumes solution adapted to problems needing a fine modelling & whose interface undergoes small deformations 2 solution algorithms : Donor Cell (1st order) & Van Leer (2nd order) easy calculation of surface tension Fluid Solver Two phase Euler / Lagrange flows Euler / Lagrange method adapted to flows with the presence of a dispersed phase diluted or dense flows monitoring each particle trajectory jet, fluid bed flows modelling, etc. Fluid Solver Two phase Euler / Lagrange flows Particle size distribution various distribution methods : uniform, gaussian, RosinRammler type, Nukiyama-Tanasawa type, user routine non uniform distribution : statistic method of Monte-Carlo wall interaction accounted for via a restitution coefficient modelling inter-particle collisions, coalescence phenomena, rupture & agglomeration Fluid Solver Turbulence Algebraic Models Baldwin- Lomax Mixing Length : Van Driest damping Abbott & Bushnell Cebeci- Smith Sub grid scale model SGS Two equations transport (k - e) & RNG Reynolds stress model (anisotropic turbulence) Fluid Solver Equations of State Perfect gas Ideal gas JWL (Jones - Wilkins - Lee) for explosions Linear - polynomial User defined Viscosity & Prandtl number Temperature functions User defined Fluid Solver Spatial discretization schemes Explicit : Van Leer Flux Vector Splitting Roe Flux Difference Splitting 3rd order Advection Upwind Splitting, HLLC Semi- implicit : Weighted Upwind Scheme QSOU Implicit : Central Difference Scheme 2rd order 3rd order Flux Limiter Scheme (Van Leer, SMART, etc.) Fluid Solver Temporal discretization scheme Explicit : Time step global minimum for transient simulations local for steady state simulations convergence acceleration Temporal Integration 6 step 2nd order Runge Kutta. Implicit: Gauss-Seidel or Jacobi iterative methods steady state calculation & low velocities. Structured solver FINITE ELEMENTS 3D beam elements 3 node shell elements 4 node tetrahedral elements Material characteristics Linear elasto-plastic, orthotropic Piecewise linear Non linear plastic Structured Solver Small deformations & large displacements Finite Elements method Large deformations Finite Elements method Finite Elements solvers Explicit / implicit Rayleigh damping Structured solver Boundary Conditions Transient or constant Outside : at nodes : temperature, forces, displacements at faces: pressure, volume forces Imposed automatically in fluids & structures Modelling displacement of fluid mesh with Updated Lagrangian method Heat transfer modelling Automatic simulation of convective & radiative heat transfer Radiation models Transparent media Automatic calculation of 3D view factors Shadow effect of intermediate obstacles Opaque Media Six-Flux model Discrete ordinate model Thermal analysis Material properties w.r.t temperature Conduction with Finite Elements method. Computation Procedure - 4 steps Fluid solver Fluid temperature Heat transfer coefficient Distribution of boundary pressures Iterations until convergence Thermal solver Transient heat transfer Solid temperature Structured solver Thermal load Mechanical load (pressure) stress & deformations FLUID-STRUCTURE REMESHING Pre - processor Mesh Multi-block structured Un-structured Delaunay method 2D & 3D meshes Hybrid, tetrahedral or hexahedral mesh Adaptative mesh Shocks, turbulent boundary layers, .. Refined mesh & automatic interpolation of the solution. Interactive, simple & automatic Complex geometries Post - processor Geometry & computation parameters visualisation during simulation. 3D colour visualisation. Multi-viewport facility : upto 30 viewports Comparison of results obtained from different computations Vectors, iso-contours, iso-surfaces & 3D current lines Translations, rotations, multi projections XY plots: residual & other parameters Animations Fluidyn - MP : STUDY CASES FLUID – STRUCTURE MECHANICAL INTERACTIONS DOOR OPENING UNDER FLUID PRESSURE AEROSPACE TOBOGGAN FLAPGATE OPENING UNDER FLUID PRESSURE TNT EXPLOSION TUNNEL (BOURGES) fluidyn-FSI FLUID – STRUCTURE INTERACTION Simulation of large displacements & large structural deformations due to fluid movements STRONG COUPLING by 2 METHODS Finite Volumes (FV) for fluids Finite Elements (FE) for solids Calculation Procedure - 4 steps Fluid Solver Fluid Temperature Coefficient of heat transfer Pressure distribution at the boundaries Iterations until convergence Heat Solver Transfer of transient heat Temperature in solids Structured solver Heat load Mechanical loads (pressures) stress & deformations fluidyn - FSI FLUID-STRUCTURE REMESHING STUDY 1 : OPENING OF A DOOR UNDER FLUID PRESSURE TARED DOOR DESCRIPTION - Opening of a door under fluid pressure effect. - Modelling with the help of the software Fluidyn - FSI fluidyn - FSI Chambre à 30 bar Porte -----> RESULTANT OF DISPLACEMENT IN THE DOOR fluidyn - FSI DOOR DEFORMATION fluidyn - FSI PRESSURE CONTOUR fluidyn - FSI PRESSURE CONTOUR fluidyn - FSI PRESSURE CONTOUR fluidyn - FSI PRESSURE CONTOUR fluidyn - FSI STUDY 2 : OPENING OF A FLAPGATE UNDER THE EFFECT OF FLUID PRESSURE PROBLEM A flapgate situated at the end of a pipe opens under the action of fluid flow - - Modelling with the help of Fluidyn - MP - fluid = water, inlet velocity = 1.07 m/s - flapgate = steel slab - 3D flow, strong coupling between fluid & structure fluidyn - FSI GEOMETRY OF THE PROCESS fluidyn - FSI DOMAIN MESH Fluid = Finite Volumes Structure = Finite Elements fluidyn - FSI FLOW IN THE MEDIAN PLANE fluidyn - FSI FLUID PRESSURE ON THE STRUCTURE fluidyn - FSI FINAL STATE fluidyn - FSI STUDY 3 : WIND RESISTANCE OF AN ESCAPE CHUTE PRESENTATION DESCRIPTION • Wind resistance of an escape chute submitted to a lateral wind of 25 nodes • Simplified Case : isolation des arcs & the runways for the simulations • Structural Modelling with the help of finite elements of beam type • Fluid Modelling (air) with the help of finite volumes • Results searched for : deformations & maximum stress CHARACTERISTICS Properties of the escape chute E 4.58E+5 N/m2 ν 0.3 ρ 5.7kg/m3 Properties of the arcs E 4.58E+5 N/m2. ν 0.3 ρ 5.7 kg/m3 Physcial properties of air Fluide Incompressible ρ 1.16924 kg/m3 Cp 1005 J.kg-1.K-1 Flow Viscous Viscosity : ν 1.895E-05 m2/s Pr 0.72 Turbulence Model k-ε FLUID MESH STRUCTURAL MESH BOUNDARY CONDITIONS RESULTS : DEFORMATIONS RESULTS : DEFORMATIONS RESULTS : RESULTANT OF DISPLACEMENT RESULTS : AERAULICS AROUND THE CHUTE STUDY 4 : TNT EXPLOSION IN A TUNNEL STUDY OF ASSOCIATED DEFORMATIONS PRESENTATION DESCRIPTION • TNT Explosion in a cylindrical section of a T tunnel • dimensions : diameter = 168 mm, lengths = 1.28 m & 1.50 m • Tunnel walls in steel, thickness = 2 mm • TNT Load of 18.5 g placed at the tunnel head • Results searched for : propagation of detonation wave, final structural deformation GEOMETRY MATHEMATICAL MODEL JWL equation for TNT r p A(1 )e R1 Ideal gas for air p ( 1)e R1 r r B(1 )e R2 R2 r e JWL EQUATION COEFFICIENTS 0 E0 Pcj Dcj cj cj = 1630 kg/ m3 = 7 GJ/m3 = 0.21 Mbar = 0.693 cm/s = 0.3 = 2.727 A B R1 R2 = 3.71213 = 0.032306 = 4.15 = 0.9 STEEL PROPERTIES • Elasticity Module • Poisson Coefficient • Density = 210 GPa = 0.3 = 7850 kg/m3 BOUNDARY CONDITIONS : FLUID BOUNDARY CONDITIONS : STRUCTURE FLUID MESH STRUCTURAL MESH 3D SIMULATION • Symmetry (in the Y direction perpendicular to the tunnel plane) : mesh reduced to half of the domain • 3D domain extended beyond the tunnel head in order to place the TNT charge • 3D Mesh – 48972 cells for the fluid – 9128 elements for the structure RESULTS : PICS OF THE PRESSURE AT MONITOR POINTS RESULTS : COMPARISON WITH EXPERIMENTAL RESULTS Computed Trace Point Time (ms) P (bar) Experimental Time (ms) P (bar) G1 0.151 30.65 0.099 31 G2 0.353 21.66 0.47 18.36 G3 0.589 13.61 0.592 16 G4 0.559 3.64 0.55 4.5 RESULTS : PRESSURE WAVE PROPAGATION RESULTS : DISPLACEMENT STRESS IN THE STRUCTURE RESULTS : DEFORMED FINAL STATE OF THE STRUCTURE CHINA Beijing S.KOREA Séoul FRANCE 7, bd de la Libération 93200 Saint-Denis Tel: 33 (0) 1 .42 43 16 66 Fax: 33 (0) 1 42 43 50 33 JAPAN Tokyo USA Lafayette, CA UK SUTTON COLDFIELD INDIA Bangalore, New Delhi FRANCE Lyon