Two way FSI

- April 16, 2024 at 10:10 am
  
  Swapnil
  Subscriber
  
  Hi,
  I am facing this error while simulation two way FSI problem.
  "MAPDL is unable to connect to the system coupling service on DESKTOP-1TN19PS through port *****. Check the -schost and -scport options on the MAPDL command line in the System Coupling analysis and ensure that the host name and the port number are correct."
  how to resolve this?
- April 16, 2024 at 12:32 pm
  
  Rahul
  Ansys Employee
  
  Hello Swapnil,
  Which version are you using?
  Is it specific to this case or happening with all the cases?
- April 16, 2024 at 1:10 pm
  
  Swapnil
  Subscriber
  
  It is working fine in 2020R1. But in recent 2023R1 and 2023R2 versions, it is showing the above error. Transient mechanical in standalone mode is working fine, the issue is in the case of co-simulations.
- April 16, 2024 at 2:21 pm
  
  Rahul
  Ansys Employee
  
  Are you using VPN?
  Sometimes restarting the system might help, have you tried restarting?
  Also check if same issue observed with latest v241 version.
  - April 17, 2024 at 4:02 am
    
    Swapnil
    Subscriber
    
    No, I am not using VPN.
    I have restarted the system but it didn't work.
- April 17, 2024 at 1:11 pm
  
  Rahul
  Ansys Employee
  
  Okay.
  Please try setting this environment variable prior to starting System Coupling.
  ANSYS_RPC_LOCALACCESSONLY=1
  Hope this helps!
- April 18, 2024 at 7:00 am
  
  Swapnil
  Subscriber
  
  Thank you. It worked for me.
  But now it is showing below error
  "The variable locations of force and heatflow variables for all Fluent |
  | participants are set to 'Node'. Make sure that this is consistent with the |
  | setup within Fluent. When importing the SCI file (this includes running |
  | inside Workbench), you can control the locations of these variables by |
  | using the 'SYC_FLUENT_CONSNODAL' environment variable"
- April 18, 2024 at 7:07 am
  
  Rahul
  Ansys Employee
  
  Please share detailed log file.
- April 18, 2024 at 7:16 am
  
  Rahul
  Ansys Employee
  
  it is recommended that you build up to the final two-way analysis incrementally, progressively adding complexity with each step. Check if your participant solutions works fine with representative loads. Look at the transcript files for errors if any.
  Please refer Building a Coupled FSI Analysis from Decoupled Participant Problems (ansys.com).
- April 18, 2024 at 9:25 am
  
  Swapnil
  Subscriber
  
  This file may contain appended logs from a sequence of runs, with the most
  recent output reported at the end of the file.
  
  ===============================================================================
  Transcript output started: 2024-04-18 12:28:20
  
  ===============================================================================
  +=============================================================================+
  | |
  | Summary of Coupling Setup |
  | |
  +=============================================================================+
  ===============================================================================
  
  +=============================================================================+
  | Coupling Participants (2) |
  +=============================================================================+
  | |
  | Participant: Fluent |
  | Type : FLUENT |
  | UpdateControls: |
  | Option : ProgramControlled |
  | Region: artery_wall |
  | Topology : Surface |
  | Input Variables : displacement |
  | Output Variables : force |
  | Variable: displacement |
  | Quantity Type : Incremental Displacement |
  | Location : Node |
  | Tensor Type : Vector |
  | Is Extensive : False |
  | Data Type : Real |
  | Variable: force |
  | Quantity Type : Force |
  | Location : Node |
  | Tensor Type : Vector |
  | Is Extensive : True |
  | Data Type : Real |
  | |
  +-----------------------------------------------------------------------------+
  | |
  | Participant: Transient Structural |
  | Type : MAPDL |
  | UpdateControls: |
  | Option : ProgramControlled |
  | Region: System Coupling Region |
  | Topology : Surface |
  | Input Variables : Force, Force_Density |
  | Output Variables : Incremental_Displacement |
  | Variable: Force |
  | Quantity Type : Force |
  | Location : Node |
  | Tensor Type : Vector |
  | Is Extensive : True |
  | Data Type : Real |
  | Variable: Incremental_Displacement |
  | Quantity Type : Incremental Displacement |
  | Location : Node |
  | Tensor Type : Vector |
  | Is Extensive : False |
  | Data Type : Real |
  | |
  +=============================================================================+
  | Analysis Control |
  +=============================================================================+
  | |
  | Analysis Type : Transient |
  | Global Stabilization : None |
  | OptimizeIfOneWay : False |
  | AllowSimultaneousUpdate : False |
  | PartitioningAlgorithm : SharedAllocateMachines |
  | |
  +=============================================================================+
  | Coupling Interfaces (1) |
  +=============================================================================+
  | |
  | Interface: interface-1 |
  | Side: One |
  | Coupling Participant : Transient Structural |
  | Region List : System Coupling Region |
  | Reference Frame : GlobalReferenceFrame |
  | Side: Two |
  | Coupling Participant : Fluent |
  | Region List : artery_wall |
  | Reference Frame : GlobalReferenceFrame |
  | Data Transfer: Data Transfer |
  | Suppress : False |
  | Target Side : Two |
  | Source Variable : Incremental_Displacement |
  | Target Variable : displacement |
  | Unmapped Value Option : Nearest Value |
  | Mapping Type : Surface Profile Preserving |
  | Convergence Target : 1.00E-02 |
  | Ramping Option : None |
  | Relaxation Factor : 8.00E-01 |
  | Data Transfer: Data Transfer 2 |
  | Suppress : False |
  | Target Side : One |
  | Source Variable : force |
  | Target Variable : Force |
  | Mapping Type : Surface Conservative |
  | Convergence Target : 1.00E-02 |
  | Ramping Option : None |
  | Relaxation Factor : 6.00E-01 |
  | Mapping Control: |
  | Absolute Gap Tolerance : 0.0 [m] |
  | Face Alignment : ProgramControlled |
  | Poor Intersection Threshold : 5.00e-01 |
  | Relative Gap Tolerance : 1.00e+00 |
  | Stop If Poor Intersection : True |
  | |
  +=============================================================================+
  | Solution Control |
  +=============================================================================+
  | |
  | Duration Option : EndTime |
  | End Time : 0.2 [s] |
  | Maximum Iterations : 15 |
  | Minimum Iterations : 1 |
  | Time Step Size : 0.0002 [s] |
  | |
  +=============================================================================+
  | Output Control |
  +=============================================================================+
  | |
  | Output Control Option : LastStep |
  | Results |
  | IncludeInstances : ProgramControlled |
  | Option : Off |
  | Write Initial Snapshot : True |
  | |
  +=============================================================================+
  
  +-----------------------------------------------------------------------------+
  | Warnings were found during data model validation. |
  +-----------------------------------------------------------------------------+
  | Warning: Participant Transient Structural (CouplingParticipant:Solution 1) |
  | has the ExecutionControl 'Option' set to 'ExternallyManaged'. System |
  | Coupling will not control the startup/shutdown behavior of this |
  | participant. |
  | Warning: Participant Fluent (CouplingParticipant:Solution) has the |
  | ExecutionControl 'Option' set to 'ExternallyManaged'. System Coupling |
  | will not control the startup/shutdown behavior of this participant. |
  +-----------------------------------------------------------------------------+
  
  +-----------------------------------------------------------------------------+
  | The variable locations of force and heatflow variables for all Fluent |
  | participants are set to 'Node'. Make sure that this is consistent with the |
  | setup within Fluent. When importing the SCI file (this includes running |
  | inside Workbench), you can control the locations of these variables by |
  | using the 'SYC_FLUENT_CONSNODAL' environment variable. For more |
  | information, refer to System Coupling User's Guide. |
  +-----------------------------------------------------------------------------+
  Awaiting connections from coupling participants...
  Transcript output stopped: 2024-04-18 12:28:25
  ===============================================================================
- April 18, 2024 at 9:27 am
  
  Swapnil
  Subscriber
  
  NUMBER OF WARNING MESSAGES ENCOUNTERED= 0
  NUMBER OF ERROR MESSAGES ENCOUNTERED= 1
  
  +——————— M A P D L S T A T I S T I C S ————————+
  
  Release: 2023 R1 Build: 23.1 Update: UP20221128 Platform: WINDOWS x64
  Date Run: 04/18/2024 Time: 12:28 Process ID: 2956
  Operating System: Windows 10 (Build: 19045)
  
  Processor Model: 12th Gen Intel(R) Core(TM) i7-12700
  
  Compiler: Intel(R) Fortran Compiler Version 19.0.5 (Build: 20190815)
  Intel(R) C/C++ Compiler Version 19.0.5 (Build: 20190815)
  Intel(R) Math Kernel Library Version 2020.0.0 Product Build 20191125
  BLAS Library supplied by Intel(R) MKL
  
  Number of machines requested : 1
  Total number of cores available : 20
  Number of physical cores available : 12
  Number of processes requested : 4
  Number of threads per process requested : 1
  Total number of cores requested : 4 (Distributed Memory Parallel)
  MPI Type: INTELMPI
  MPI Version: Intel(R) MPI Library 2021.5 for Windows* OS
  
  GPU Acceleration: Not Requested
  
  Job Name: file0
  Input File: dummy.dat
  
  Core Machine Name Working Directory
  —————————————————–
  0 DESKTOP-1TN19PS F:\Two way FSI\_ProjectScratch\ScrDA12
  1 DESKTOP-1TN19PS F:\Two way FSI\_ProjectScratch\ScrDA12
  2 DESKTOP-1TN19PS F:\Two way FSI\_ProjectScratch\ScrDA12
  3 DESKTOP-1TN19PS F:\Two way FSI\_ProjectScratch\ScrDA12
  
  Latency time from master to core 1 = 2.043 microseconds
  Latency time from master to core 2 = 2.096 microseconds
  Latency time from master to core 3 = 3.560 microseconds
  
  Communication speed from master to core 1 = 13728.96 MB/sec
  Communication speed from master to core 2 = 14491.18 MB/sec
  Communication speed from master to core 3 = 10225.86 MB/sec
  
  Total CPU time for main thread : 1.2 seconds
  Total CPU time summed for all threads : 1.0 seconds
  
  Elapsed time spent obtaining a license : 0.3 seconds
  Elapsed time spent pre-processing model (/PREP7) : 0.0 seconds
  Elapsed time spent solution – preprocessing : 0.0 seconds
  Elapsed time spent computing solution : 0.0 seconds
  Elapsed time spent solution – postprocessing : 0.0 seconds
  Elapsed time spent post-processing model (/POST1) : 0.0 seconds
  
  Sum of memory used on all processes : 17.0 MB
  Sum of memory allocated on all processes : 5184.0 MB
  Physical memory available : 32 GB
  
  Total amount of I/O written to disk : 0.0 GB
  Total amount of I/O read from disk : 0.0 GB
  
  +—————— E N D M A P D L S T A T I S T I C S ——————-+
  
  *—————————————————————————–*
  | |
  | RUN COMPLETED |
  | |
  |—————————————————————————–|
  | |
  | Ansys MAPDL 2023 R1 Build 23.1 UP20221128 WINDOWS x64 |
  | |
  |—————————————————————————–|
  | |
  | Database Requested(-db) 1024 MB Scratch Memory Requested 1024 MB |
  | Max Database Used(Master) 1 MB Max Scratch Used(Master) 1 MB |
  | Max Database Used(Workers) 1 MB Max Scratch Used(Workers) 4 MB |
  | Sum Database Used(All) 4 MB Sum Scratch Used(All) 13 MB |
  | |
  |—————————————————————————–|
  | |
  | CP Time (sec) = 0.984 Time = 12:28:25 |
  | Elapsed Time (sec) = 2.000 Date = 04/18/2024 |
  | |
  *—————————————————————————–*
- April 18, 2024 at 9:33 am
  
  Rahul
  Ansys Employee
  
  When running System Coupling and it stops running, the first thing to do is examine the output files for each solver to look for clues to what happened. For Fluent, look at the transcript .trn file. For Mechanical, look at the .out file. Also, look at the System Coupling log file, scl.
  I recommend going over this tutorial in the Ansys documentation that shows a 2-way FSI simulation with Fluent and Mechanical. https://ansyshelp.ansys.com/account/secured?returnurl=/Views/Secured/corp/v221/en/sysc_tut/sysc_tut_reedvalve_fluent.html
  if this tutorial works well, consider checking your participant setups again to see if it is correctly defined.
- April 18, 2024 at 12:15 pm
  
  Swapnil
  Subscriber
  
  I tried the reed valve FSI simulation from the manual, but it encountered the following.
  system coupling log file gives " Awaiting connections from coupling participants..."
  while on the console screen it is showing following...
  ===============================================================================
  +=============================================================================+
  | |
  | Summary of Coupling Setup |
  | |
  +=============================================================================+
  ===============================================================================
  
  +=============================================================================+
  | Coupling Participants (2) |
  +=============================================================================+
  | |
  | Participant: Fluid Flow (Fluent) |
  | Type : FLUENT |
  | UpdateControls: |
  | Option : ProgramControlled |
  | Region: fsi |
  | Topology : Surface |
  | Input Variables : displacement |
  | Output Variables : force |
  | Variable: displacement |
  | Quantity Type : Incremental Displacement |
  | Location : Node |
  | Tensor Type : Vector |
  | Is Extensive : False |
  | Data Type : Real |
  | Variable: force |
  | Quantity Type : Force |
  | Location : Element |
  | Tensor Type : Vector |
  | Is Extensive : True |
  | Data Type : Real |
  | |
  +-----------------------------------------------------------------------------+
  | |
  | Participant: MAPDL Transient |
  | Type : MAPDL |
  | UpdateControls: |
  | Option : ProgramControlled |
  | Region: FSIN_1_System Coupling Region |
  | Topology : Surface |
  | Input Variables : Force, Force_Density |
  | Output Variables : Incremental_Displacement |
  | Variable: Force |
  | Quantity Type : Force |
  | Location : Node |
  | Tensor Type : Vector |
  | Is Extensive : True |
  | Data Type : Real |
  | Variable: Incremental_Displacement |
  | Quantity Type : Incremental Displacement |
  | Location : Node |
  | Tensor Type : Vector |
  | Is Extensive : False |
  | Data Type : Real |
  | |
  +=============================================================================+
  | Analysis Control |
  +=============================================================================+
  | |
  | Analysis Type : Transient |
  | Global Stabilization : None |
  | OptimizeIfOneWay : True |
  | AllowSimultaneousUpdate : False |
  | PartitioningAlgorithm : SharedAllocateMachines |
  | |
  +=============================================================================+
  | Coupling Interfaces (1) |
  +=============================================================================+
  | |
  | Interface: Coupling Interface 1 |
  | Side: One |
  | Coupling Participant : Fluid Flow (Fluent) |
  | Region List : fsi |
  | Reference Frame : GlobalReferenceFrame |
  | Side: Two |
  | Coupling Participant : MAPDL Transient |
  | Region List : FSIN_1_System Coupling Region |
  | Reference Frame : GlobalReferenceFrame |
  | Data Transfer: Force |
  | Suppress : False |
  | Target Side : Two |
  | Source Variable : force |
  | Target Variable : Force |
  | Mapping Type : Surface Conservative |
  | Convergence Target : 1.00E-02 |
  | Ramping Option : None |
  | Relaxation Factor : 1.00E+00 |
  | Data Transfer: displacement |
  | Suppress : False |
  | Target Side : One |
  | Source Variable : Incremental_Displacement |
  | Target Variable : displacement |
  | Unmapped Value Option : Nearest Value |
  | Mapping Type : Surface Profile Preserving |
  | Convergence Target : 1.00E-02 |
  | Ramping Option : None |
  | Relaxation Factor : 1.00E+00 |
  | Mapping Control: |
  | Absolute Gap Tolerance : 0.0 [m] |
  | Face Alignment : ProgramControlled |
  | Poor Intersection Threshold : 5.00e-01 |
  | Relative Gap Tolerance : 1.00e+00 |
  | Stop If Poor Intersection : True |
  | |
  +=============================================================================+
  | Solution Control |
  +=============================================================================+
  | |
  | Duration Option : EndTime |
  | End Time : 1.00e-02 |
  | Maximum Iterations : 10 |
  | Minimum Iterations : 1 |
  | Time Step Size : 1.00e-04 |
  | |
  +=============================================================================+
  | Output Control |
  +=============================================================================+
  | |
  | Output Control Option : EveryStep |
  | Results |
  | IncludeInstances : ProgramControlled |
  | Option : ProgramControlled |
  | Type |
  | Option : EnsightGold |
  | Write Initial Snapshot : True |
  | |
  +=============================================================================+
  
  +=============================================================================+
  | Execution Information |
  +=============================================================================+
  | |
  | System Coupling |
  | Command Line Arguments: |
  | --guiserver -m cosimgui |
  | Working Directory: |
  | F:\ReedValve |
  | |
  | Fluid Flow (Fluent) |
  | Execution Command: |
  | "C:\PROGRA~1\ANSYSI~1\v231\fluent\ntbin\win64\fluent.exe" 3ddp -g -scpo |
  | rt=56975 -schost=localhost -scname="Fluent_1" -i Fluent_1.jou |
  | Working Directory: |
  | F:\ReedValve\Fluent_1 |
  | |
  | MAPDL Transient |
  | Execution Command: |
  | "C:\PROGRA~1\ANSYSI~1\v231\ansys\bin\winx64\ANSYS231.exe" -b nolist -s |
  | noread -scport 56975 -schost localhost -scname "Mechanical_2" -i "Mecha |
  | nical.dat" -o Mechanical_2.out |
  | Working Directory: |
  | F:\ReedValve\Mechanical_2 |
  | |
  +=============================================================================+
  Awaiting connections from coupling participants...Traceback (most recent call last):
  File "PyLib\kernel\remote\RemoteObjects.py", line 190, in CreateRemoteObject
  File "PyLib\cosimulation\remoteclient\Client.py", line 11, in __init__
  File "pyExt\PhysicsCouplingAnsRpcWrapper.py", line 129, in __init__
  RuntimeError
  
  Traceback (most recent call last):
  File "PyLib\kernel\server\JsonRpc.py", line 196, in methodCallHandlerCore
  File "PyLib\kernel\server\JsonRpc.py", line 145, in impl
  File "PyLib\kernel\server\JsonRpc.py", line 48, in executeCommand
  File "PyLib\kernel\commands\CommandDefinition.py", line 75, in func
  File "PyLib\kernel\commands\__init__.py", line 30, in executeCommand
  File "PyLib\kernel\commands\CommandManager.py", line 165, in executeCommand
  File "PyLib\cosimulation\externalinterface\core\solver.py", line 137, in execute
  File "PyLib\cosimulation\solver\__init__.py", line 151, in solve
  File "PyLib\kernel\util\Memory.py", line 209, in wrapper
  File "PyLib\cosimulation\solver\__init__.py", line 550, in __startParticipantsControlled
  File "PyLib\cosimulation\participantmanager\couplingparticipant\OldApisParticipant.py", line 137, in completeParticipantSetup
  File "PyLib\cosimulation\participantmanager\couplingparticipant\OldApisParticipant.py", line 378, in __reachInitialSyncPoint
  File "PyLib\cosimulation\remoteclient\__init__.py", line 42, in setRequest
  KeyError: 'Fluent_1'