Fluid-Structure Interaction (FSI) with System Coupling Dr Jasper Kidger ANSYS UK Ltd. 1
System Coupling (FSI) Introduction 2
Outline Review of pre-r14 Solutions for ANSYS Fluent Motivation for System Coupling Features available Demonstration of using System Coupling Gallery Questions 3
Brief Review of Pre R14 FSI Solutions for ANSYS Fluent 4
One-Way FSI in Workbench Default approach in Workbench is where data is transferred and mapped using ANSYS CFD-Post Supports both thermal and structural loads Surface Temperature Heat Transfer Coefficient Pressure (i.e. Stress Vector) Volumetric Temperature All non-conservative mapping even for similar meshes 5
Outside of Workbench 1-way FSI could be performed using a the FSI Mapping Toolkit in Fluent. Compute CFD solution first Read FEA mesh into Fluent Fluent acts as an interpolation tool, exporting CFD results at FEA mesh locations 2-way FSI required an external software tool (MpCCI from Fraunhofer SCAI) Required additional 3 rd party license 6
System Couplings Motivation 7
Introducing System Couplings General Motivation Common tool within Workbench for 2-way transfer of data between any of our solvers. - Rather than having a specific import tool for each solver combination: - ANSYS Mechanical has a function for Fluent data import - And another function for CFX data import - Etc... Each solver needs just oneadaptor to exchange data with the coupling server - Therefore any solver that is SC enabled can exchange data with any other - ANSYS Mechanical exchanges data with just System Coupling 8
Generalized Vision for System Couplings in Workbench Coupling Source Data (External) Coupling Source Data (Solvers) Co-Simulation (Solvers) Solver X Structural Solver X Structural Solver System Transient Structural Solver System Transient Structural Available Planned R15+ at at R14.5 for FLUENT/Mechanical Solvers 9
What is Supported at R14? 10
System Coupling 14.0: A Broad Range of Capabilities Two-way surface (3D) force/displacement coupling with ANSYS Fluent and ANSYS Mechanical Workbench based setup and execution Parameterization, design exploration and optimization Windows (32/64-bit) and Linux (64-bit) Integrated post-processing with ANSYS CFD-Post Parallel processing for both Fluent and Structural/Mechanical solutions with ANSYS HPC Restarts for fluid-structure interaction No special licensing required other than minimum ANSYS license must be Structural 11
Technical Review (Workflow) 12
System Coupling Schematic Setup 13
System Coupling Controls the Participant Solvers for Transient and Steady/Static Solutions Solution update can ONLY be done via System Coupling component System Coupling ensures that the time duration and time step settings are consistent across all participant solvers 14
Setup Transient/Static Structural Model Setup structural solution, structural boundary conditions and Fluid-Solid Interface 15
Setup Fluid Flow (FLUENT) Model Setup fluid solution, fluid boundary conditions and specify System Coupling Dynamic Mesh Zone for fluid-structure interaction motion 16
Update Setup Cells for Transient/Static Structural and Fluid Flow (FLUENT) State of System Coupling setup cell will be Upstream data is now available for SC Setup 17
System Coupling GUI Outline Chart Monitors Details Solution Information Text Monitors 18
System Coupling Analysis Settings Coupling End Time If both participants are transient For General, Number of Steps is user input Coupling Step Size If both participants are transient Note this overwrites values set in Fluent / Mechanical interfaces Minimum Number of Iterations per Coupling Step Maximum Number of Iterations per Coupling Step 19
System Coupling Participants are Transient/Static Structural and Fluid Flow (FLUENT) Region and variable information is generated automatically via Update when analysis systems are first connected to System Coupling For Fluent, all regions of type Wall are shown in SC Setup For Mechanical, all regions of type Fluid-Solid Interface are shown in SC Setup 20
Recommended Way to Create Data Transfer Regions Use Ctrl key to select a Fluent and Mechanical region pair and select Create Data Transfer from rightclick pop-up menu Automatically fills in the details for the data transfer region Data transfers can be one-way (i.e. only transfer force or only transfer displacement) or two-way 21
Create Data Transfers 22
Participant Region Variable Data Transfer Defines the Details for the Source, Target and Data Transfer Controls Transfer At Start of Iteration only Under Relaxation Factor Convergence Target 23
Execution Control Co-Simulation Sequence Transient or Static Structural will always be first in the co-simulation sequence Debug Output Different levels of debug output for analysis and data transfers Intermediate Results File Output Controls the intervals for writing restart file information 24
Executing System Coupling 25
Alternative Method for Executing System Coupling From schematic select Update using right-click menu on System Coupling solution cell Solution progress (% complete) can be monitored using View Progress menu 26
Solution Information Build information Complete summary of coupling service input file Analysis details Participant summaries Data transfer details Mapping diagnostics Time step and iteration summary Solver field equation convergence summary Data transfer convergence summary Fluent/MAPDL solver output 27
Chart Monitors X-axis can be coupling time, step or iteration. Default chart monitors show convergence history for all data transfers. 28
Post Processing System Coupling Transient/Static Structural or Fluid Flow (FLUENT) Results cell for solver-specific post-processing Connect structural Solution cell directly to Fluent system Results cell or add a Results System (ANSYS CFD-Post) for unified post-processing of structural and fluid results 29
Post Processing System Coupling Oscillating Plate Verification Excellent correlation between System Coupling, published data and MFX solver 30
Application Examples 31
Tank Sloshing Transient free surface flow in a liquid storage tank with baffles Tank is excited by a time varying gravitational load for a duration of 10s Baffles are non-metallic and fixed to the tank with an adhesive Forces are transferred (one-way only) via co-simulation to determine the stresses acting on the baffles Determine the integrity and viability of the adhesive bonding Animation shows combined postprocessing of ANSYS Fluent and ANSYS Mechanical results in ANSYS CFD-Post 32 Laz Foley: ANSYS (Evanston)
AGARD Wing AGARD 445.6 test case Mahogany wood Zero angle of attack Hexahedral mesh with diffusion based smoothing in Fluent Compressible flow (0.8 Mach) Initialized from pre-solved steady state flow solution 33 Ashok Khondge: ANSYS (India)
Liquid Pouring Gulping liquid stream behavior in a non-rigid package/carton design Determine how pouring is affected by package design, opening design and fluid properties Diffusion based smoothing used in Fluent to cater for deformation of package walls Fluent models used include VOF and LES This tightly coupled solution requires stabilization method for successful analysis Model courtesy of Tetra Pak 34
Three-Leaf Valve 35 Transient blood flow through a threeleaf valve Symmetry used with 1/6 th of fluid domain Non-Newtonian fluid (i.e. blood) defined in Fluent Re-meshing and smoothing in Fluent Alternatively, use diffusion based smoothing Non-Linear contact in Transient Structural to cater for closure of valve leaflets Blood vessel wall has combination of isotropic and anisotropic (no-linear) materials Laz Foley: ANSYS (Evanston)
Online Resources and Documentation 36
System Coupling Documentation 37 Available in HTML and PDF Formats
System Coupling Tutorial Tutorial input file available on ANSYS Customer Portal by using the Download Wizard to download ANSYS_Fluid_Dynamics_Tutorial_Inputs.zip 38
Best Practices User documentation contains a dedicated section on Best Practice Guidelines for Using System Coupling 39
Training Course 2-day Training course is currently being written for System Coupling Predicted to be ready in March 2012 40
Any Questions? 41