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