2Fluid-Structure Interaction (FSI) A Fluid-Structure Interaction model is needed when:there are heavy fluid actions ondeforming boundariesit is not possible to neglectdeformationsphenomena are coupled and it is notpossible to study the problemseparating the structural and fluideffectse.g. Hemodynamics FSI problem
3Benefits of FSI Simulation Investigate if problems are coupledDetermine global performance difference comparing with the rigid caseAnalyze local flow field changesAnalyze structural dynamic behaviourStructural verificationInvestigate if problems are physically stable/unstable and determine transition conditions
4The Proposed ProductThe Product aim is to allow FSI problems simulation entirely within ANSYS FluentA dedicated FEM solver has been developed by means of UDF coding as plug in for ANSYS FluentDedicated Graphical User Interface (GUI) and Text User Interface have been developedThe Product has been tested, validated and used to simulate practical and industrial cases
5Our Strategy New: The product allows to set structure material More Time Steps?NOPOST-PROCESSINGCFD MeshCFD MaterialsCFD IterationsCFD BCsFEM MaterialsFEM BCsNext TimestepNew:The product allows toset structure materialproperties and constraintsin the ANSYS FLUENTcode.Convergence?NOINITIALIZATIONRemeshing/SmoothingPressures, shearstresses andcontact forcesDisplacementsFEM Mesh is builtFEM IterationNew geometryfrom CFD one
6Product Features General robust FEM solver implemented Structural simulations in the range of small and large displacements, including non linear and contact problems2D model for beams with implicit and explicit FEM approach3D model for shells structure with implicit and explicit FEM approachParallel implementationStatic and dynamic transient analysisMultiphase and turbulence ANSYS Fluent modelPost-processing with ANSYS Fluent
7Product strengths High efficiency Very light General purpose The result is a very light code that leaves almostunaffected the global CPU timeHigh efficiencyVery lightGeneral purposeANSYS Fluent users orientedThere are no interpolation errorsNo other software knowledge is requiredHighly customizable for client-oriented solutions, services and consultancy.
8Graphical User Interface Dedicated GUI in ANSYS Fluent
9The CFD point of viewVery often FSI problems are analysed by a structural point of view simulating the fluid with too simplified modelsThe present approach uses the CFD point of view (ANSYS Fluent users point of view), focusing on how the interaction with the structure influences the fluid behaviourThe CFD user is now allowed to set structure material properties and constraints in order to easily simulate its presence in a very family wayThe knowledges of other software packages are not required
10Example of 3D model for shells structure (1) FSI Interaction between a rectangular curtain and an air flow in a room.This is an example in whichbecause there are heavy fluid actions on the curtain surfaceand so it is necessary to consider its deformationsit is not possible to study the problem separatingstructural and fluid effectsWINDOWDOORCURTAIN
11Example of 3D model for shells structure (2) HW & SW configurationHardware:2 AMD Opteron 2,2GHz Processor16Gb RAMSoftware:OS Linux Fedora 6ANSYS Fluent VersionVersion: 3ddpStructural analysis solver used:Explicit
12Example of 3D model for shells structure (3) Case 1:The curtain has the top edge constrained. It’s moved by the air flowentering from the window and subjected to its dead load.
13Example of 3D model for shells structure (4) Case 2:In this case the event of failure of curtain support is investigated.The curtain is pushed by the air flow entering from the window andit’s free to fall because the top edge constraint is missing.
14Example of related areas Hemodynamics and FSI Fluid-Structure InteractionIn this branch of medicine is necessary to consider the interactionbetween the flowing blood and the vessels walls in order to investigateand study many hemodynamics problems.HW & SW configurationHardware:2 AMD Opteron 2,2GHz Processor16Gb RAMSoftware:OS Linux Fedora 6ANSYS Fluent VersionVersion: 3ddpStructural analysis solver used:Implicit solver working with MSC.NASTRAN solver
15Example of hemodynamics problem (1) The following picture represents the model of a Systemic-to-pulmonaryshunt that is a surgical procedure to treat complex congenital heartdefects.It consists of an interposing tube between the sub-clavian artery andthe right pulmonary artery. In this caseit’s important to analyze the pressure drop across the shuntwhich is affected by the blood pressure combinedwith the distensibility of the shunt.