Fluid-Structure Interaction (FSI) with System Coupling UK/staticassets... · Fluid-Structure...

Fluid-Structure Interaction (FSI) with System Coupling

© 2012 ANSYS, Inc. February 23, 20121

Dr Jasper Kidger

ANSYS UK Ltd.

System Coupling (FSI) Introduction


• Review of pre-R14 Solutions for ANSYS Fluent

• Motivation for System Coupling

• Features available

Outline


• Demonstration of using System Coupling

• Gallery

• Questions

Brief Review of “Pre” R14 FSI Solutions for ANSYS Fluent


One-Way FSI in Workbench

• Default approach in Workbench is where data is transferred and


• 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

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


CFD results at FEA mesh locations

• 2-way FSI required an external software tool (MpCCI from Fraunhofer SCAI)

– Required additional 3rd party license

System Couplings 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

Introducing System Couplings

General Motivation


- And another function for CFX data import

- Etc...

• Each solver needs just one adaptor 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

Generalized Vision for System Couplings in Workbench

Structural

Solver ‘X’

Co-Simulation

(Solvers)

Coupling Source Data

(Solvers)

Coupling Source Data

(External)

Structural

Solver ‘X’


Available at R14Available at R14R15+R15+Planned at R14.5 for FLUENT/Mechanical SolversPlanned at R14.5 for FLUENT/Mechanical Solvers

Transient Structural

Solver System

Transient Structural

Solver System

R15+R15+

What is Supported at R14?


• 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

System Coupling 14.0: A Broad Range of Capabilities


• 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

Technical Review(Workflow)


System Coupling Schematic Setup


• 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

System Coupling Controls the Participant Solvers for Transient and Steady/Static Solutions


Setup Transient/Static Structural Model


Setup structural solution,

structural boundary

conditions and Fluid-Solid

Interface

Setup Fluid Flow (FLUENT) Model


Setup fluid solution, fluid

boundary conditions and specify

System Coupling Dynamic Mesh

Zone for fluid-structure interaction

motion

• State of System Coupling setup cell will be

– Upstream data is now available for SC Setup

Update Setup Cells for Transient/Static Structural and Fluid Flow (FLUENT)


System Coupling GUI

Chart

MonitorsOutline


Solution Information

Text MonitorsDetails

• Coupling End Time

– If both participants are transient

– For General, Number of Steps is

user input

• Coupling Step Size


System Coupling Analysis Settings



– Note this overwrites values set in

Fluent / Mechanical interfaces

• Minimum Number of Iterations per

Coupling Step

• Maximum Number of Iterations per

Coupling Step

• Region and variable information is

generated automatically via

Update when analysis systems are

first connected to System

Coupling

System Coupling Participants are Transient/Static Structural and Fluid Flow (FLUENT)


• 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

• Use Ctrl key to select a Fluent and

Mechanical region pair and select

Create Data Transfer from right-

click pop-up menu

• Automatically fills in the details

Recommended Way to Create Data Transfer Regions


• 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

Create Data Transfers


• Participant

• Region

• Variable

• Transfer At

– Start of Iteration only

Data Transfer Defines the Details for the Source, Target and Data Transfer Controls


– Start of Iteration only

• Under Relaxation Factor

• Convergence Target

• 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

Execution Control


analysis and data transfers

• Intermediate Results File Output

– Controls the intervals for writing restart

file information

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

Alternative Method for Executing System Coupling


• Build information

• Complete summary of coupling

service input file

• Analysis details

• Participant summaries

• Data transfer details

Solution Information


• Data transfer details

• Mapping diagnostics

• Time step and iteration summary

• Solver field equation convergence

summary

• Data transfer convergence

summary

• Fluent/MAPDL solver output

Chart Monitors


Default chart monitors

show convergence

history for all data

transfers.

X-axis can be

coupling time,

step or

iteration.

• 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

Post Processing System Coupling


• Oscillating Plate Verification

– Excellent correlation between

System Coupling, published

data and MFX solver

Post Processing System Coupling


Application Examples


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 post-

processing of ANSYS Fluent and ANSYS

Mechanical results in ANSYS CFD-Post

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)

© 2012 ANSYS, Inc. February 23, 201233 Ashok Khondge: ANSYS (India)

• Compressible flow (0.8 Mach)

• Initialized from pre-solved steady

state flow solution

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


Fluent to cater for deformation of

package walls

• Fluent models used include VOF and LES

• This “tightly” coupled solution requires

stabilization method for successful

analysisModel courtesy of Tetra Pak

Three-Leaf Valve

• Transient blood flow through a three-

leaf valve

• Symmetry used with 1/6th 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


System Coupling Documentation

© 2012 ANSYS, Inc. February 23, 201237 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

Best Practices


• User documentation contains a dedicated section on

Best Practice Guidelines for Using System Coupling

Training Course• 2-day Training course is currently being written for System Coupling

• Predicted to be ready in March 2012


Any Questions?


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