NUMERICAL MODELLING OF MECHANICAL COUPLING IN FLUIDS & STRUCTURES
SOFTWARE fluidyn - MP
PRESENTATION OF fluidyn - MP
General : role & utility of Computational Fluid DynamicsA 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, pressure, temperature, etc.) at each point in the domain
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
3-DimensionsCompressible / incompressibleMechanical / thermal shocks Viscous / non-viscousLaminar / turbulentMulti-speciesMulti-phaseSolution of Navier-Stokes EquationsFluid Solver
Non-Newtonian Flows : Bingham lawPower law
Chemical combustion reactions Arrhenius modelEddy-break-up modelEddy dissipation model
Deflagration & fireBLEVEPool fire
DetonationJWL model
Two phase flows droplets, bubbles, particlesEuler-Lagrange Monte-Carlo, Free surface flow ( VOF method + CSF method)
Fluid Solver
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 SolverFree 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 SolverFree surface two phase 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 SolverTwo phase Euler / Lagrange flows
Particle size distribution
various distribution methods : uniform, gaussian, Rosin-Rammler 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 SolverTwo phase Euler / Lagrange flows
Algebraic ModelsBaldwin- LomaxMixing Length :Van Driest dampingAbbott & BushnellCebeci- SmithSub grid scale model SGS Two equations transport (k - e) & RNGReynolds stress model (anisotropic turbulence) TurbulenceFluid Solver
Perfect gasIdeal gasJWL (Jones - Wilkins - Lee) for explosionsLinear - polynomialUser defined
Equations of StateTemperature functionsUser defined
Viscosity & Prandtl numberFluid Solver
Spatial discretization schemesExplicit : Van Leer Flux Vector Splitting Roe Flux Difference Splitting 3rd order Advection Upwind Splitting, HLLCSemi- implicit : Weighted Upwind Scheme QSOU 2rd order Implicit : Central Difference Scheme 3rd order Flux Limiter Scheme (Van Leer, SMART, etc.)
Fluid Solver
Explicit :Time stepglobal minimum for transient simulations local for steady state simulationsconvergence acceleration Temporal Integration 6 step 2nd order Runge Kutta.
Implicit:Gauss-Seidel or Jacobi iterative methodssteady state calculation & low velocities.Temporal discretization schemeFluid 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
Structured Solver Small deformations & large displacements Finite Elements method
Large deformationsFinite Elements method
Finite Elements solversExplicit / implicit
Rayleigh damping
Boundary Conditions Transient or constant
Outside : at nodes : temperature, forces, displacementsat faces: pressure, volume forces
Imposed automatically in fluids & structures
Modelling displacement of fluid mesh with Updated Lagrangian methodStructured solver
Automatic simulation of convective & radiative heat transfer
Radiation modelsTransparent mediaAutomatic calculation of 3D view factors Shadow effect of intermediate obstaclesOpaque MediaSix-Flux modelDiscrete ordinate modelThermal analysisMaterial properties w.r.t temperatureConduction with Finite Elements method.Heat transfer modelling
Computation Procedure - 4 steps
Multi-block structured
Un-structured
Delaunay method2D & 3D meshesHybrid, tetrahedral or hexahedral mesh
Adaptative meshShocks, turbulent boundary layers, ..Refined mesh & automatic interpolation of the solution.
Interactive, simple & automaticComplex geometries
MeshPre - 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
AnimationsPost - processor
Fluidyn - MP : STUDY CASESFLUID STRUCTURE MECHANICAL INTERACTIONSDOOR OPENING UNDER FLUID PRESSUREFLAPGATE OPENING UNDER FLUID PRESSUREAEROSPACETOBOGGANTNT EXPLOSION TUNNEL (BOURGES)
fluidyn-FSIFLUID 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 stepsfluidyn - FSI
STUDY 1 : OPENING OF A DOOR UNDER FLUID PRESSURE
TARED DOORDESCRIPTION
- Opening of a door under fluid pressure effect.- Modelling with the help of the software Fluidyn - FSI
Porte ----->Chambre 30 barfluidyn - FSI
RESULTANT OF DISPLACEMENT IN THE DOORfluidyn - FSI
DOOR DEFORMATION fluidyn - FSI
PRESSURE CONTOURfluidyn - FSI
PRESSURE CONTOUR fluidyn - FSI
PRESSURE CONTOURfluidyn - FSI
PRESSURE CONTOURfluidyn - FSI
STUDY 2 : OPENING OF A FLAPGATE UNDER THE EFFECT OF FLUID PRESSURE
fluidyn - FSI- 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
PROBLEM
GEOMETRY OF THE PROCESSfluidyn - FSI
DOMAIN MESHFluid = Finite Volumes Structure = Finite Elementsfluidyn - FSI
FLOW IN THE MEDIAN PLANEfluidyn - FSI
FLUID PRESSURE ON THE STRUCTUREfluidyn - FSI
FINAL STATEfluidyn - FSI
STUDY 3 : WIND RESISTANCE OF AN ESCAPE CHUTE
DESCRIPTION
Wind resistance of an escape chute submitted to a lateral wind of 25 nodesSimplified Case : isolation des arcs & the runways for the simulationsStructural Modelling with the help of finite elements of beam typeFluid Modelling (air) with the help of finite volumesResults searched for : deformations & maximum stressPRESENTATION
CHARACTERISTICS
Properties of the escape chute
E
4.58E+5 N/m2
0.3
5.7kg/m3
Properties of the arcs
E
4.58E+5 N/m2.
0.3
5.7 kg/m3
Physcial properties of air
Fluide
Incompressible
1.16924 kg/m3
Cp
1005 J.kg-1.K-1
Flow
Viscous
Viscosity:
1.895E-05 m2/s
Pr
0.72
Turbulence Model
k-
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 TUNNELSTUDY OF ASSOCIATED DEFORMATIONS
DESCRIPTION
TNT Explosion in a cylindrical section of a T tunneldimensions : diameter = 168 mm, lengths = 1.28 m & 1.50 m Tunnel walls in steel, thickness = 2 mmTNT Load of 18.5 g placed at the tunnel headResults searched for : propagation of detonation wave, final structural deformationPRESENTATION
GEOMETRY
JWL equation for TNT
Ideal gas for airMATHEMATICAL MODEL
JWL EQUATION COEFFICIENTS0= 1630 kg/ m3A= 3.71213E0= 7 GJ/m3B= 0.032306Pcj= 0.21 MbarR1= 4.15Dcj= 0.693 cm/sR2= 0.9cj= 0.3cj= 2.727
Elasticity Module = 210 GPaPoisson Coefficient= 0.3Density= 7850 kg/m3STEEL PROPERTIES
BOUNDARY CONDITIONS : FLUID
BOUNDARY CONDITIONS : STRUCTURE
FLUID MESH
STRUCTURAL MESH
Symmetry (in the Y direction perpendicular to the tunnel plane) : mesh reduced to half of the domain3D domain extended beyond the tunnel head in order to place the TNT charge3D Mesh48972 cells for the fluid9128 elements for the structure3D SIMULATION
RESULTS : PICS OF THE PRESSURE AT MONITOR POINTS
RESULTS : COMPARISON WITH EXPERIMENTAL RESULTS
RESULTS : PRESSURE WAVE PROPAGATION
RESULTS : DISPLACEMENT STRESS IN THE STRUCTURE
RESULTS : DEFORMED FINAL STATE OF THE STRUCTURE
UKSUTTON COLDFIELDFRANCELyonCHINABeijingJAPANTokyo
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