Help with multiphysics

[Anonymous]

Hi I am Asif

I need help simulating, fluid flow through a porous medium. I created a solid cylinder in inventor with a inlet and outlet. The fluid I want to use to perform the simulation is air. I want to find the pressure on the porous medium, with a velocity of 20cm/min coming out the outlet. I having problems trying to simulate this scenario. I look at the tutorials provided, but it does not help. Can you please assist me with this task.

[Joey.X]

Hi, Sultan9009

Here are steps for flow through porous media (combination of porous parts and regular fluid parts). 

- In CAD modeling, set the porous material as part(or multiple parts), and push the CAD into simulation. Or read CAD assembly from SIMMP. 

- In SIMMP/FEDEditor/tree view, select porous part(s), select element definition, under "general", change Viscosity model to "Porous media model"; under Orientation, set material model as Isotropic or Orthotropic, for orthotropic, the material axis etc. need to be specified. 

-  In SIMMP/FEDEditor/tree view/porous part(s), right click Material, define porous material properties such as permeability, inertial coefficient etc. 

Attached is a simple 2D planar model for your reference.

[Anonymous]

Autodesk (R) Simulation Steady Fluid Flow

Version 2012.00.00.0163-W64/X64 04-Mar-2011

Copyright (c) 2011, Autodesk, Inc. All rights reserved.

 ----------------------------------------------------------------

    Date & Time         : 06-20-2012  14:01:54

    Input File          : E:\Reactor.ds_data\4\ds        

    Command Line Options: -silent-x721724

    PROGRAM               VERSION: 201200000163

    Alg-win-x64.DLL       VERSION: 201200000163

    AlgConfig-win-x64.DLL VERSION: 201200000163

    Agsdb_ar-win-x64.DLL  VERSION: 201200000163

    AlgSolve.exe          VERSION: 201200000163

 ----------------------------------------------------------------

 **** Starting main program

 **** Model Unit System Settings:

      --------------------------------------------

       Unit System              : English (in)

       Force                    : lbf

       Length                   : in

       Time                     : s

       Temperature (Absolute)   : deg F (R)

       Thermal Energy           : in*lbf

       Voltage                  : V

       Current                  : A

       Electrical Resistance    : ohm

       Mass                     : lbf*s^2/in

      --------------------------------------------

 **** Memory dynamically allocated = 31042 KB (1% of physical memory)

 **** Generating coordinates

 **** Generating initial conditions

 **** Generating boundary conditions

 **** FEA information

      Model Dimension........................... =   3D model

      The number of nodes....................... =   18650

      The number of elements.................... =   56266

      The number of equations................... =   69384

 **** Segregated Scheme Data

      Select segregated scheme ................. =   T

      Solver for momentum equations ............ =   Automatic          

      Solver for pressure equations ............ =   Automatic          

      Velocity relaxation factor ............... =   7.000E-01

      Pressure relaxation factor ............... =   5.000E-01

      Inertial relaxation factor ............... =   1.000E+00

      Apply automatic adaptive parameter control =   T

      ID of Detect stagnation due to oscillation =   1

      The number of equations (U)............... =   16999

      The number of equations (V)............... =   16999

      The number of equations (W)............... =   16866

      The number of equations (P)............... =   18520

 **** Turbulence Model Data..................... =   Off

 **** Proceeding with Equal-Order Segregated Method

 **** ENTERING TIME LOOP

 Step                                        NonL. Solv. == Euclid L-2 Norm ==

 Intv  Step     Time   Percent    DT      L  Iter  Iter   R_Norm_V    R_Norm_P

    1     1  1.000E+00   0.00  1.000E+00  1          50   |R/F|u =  NaN     

 **** Error: Divergence detected in iterative solver.

             Please try sparse solver.

Can you help me with this error?

[Joey.X]

This error most probally came from improper model setting such as boundary conditions, could you share your model setups and mesh info? 

You can also try sparse equation solver which is more robust bet less speedy than default iterative solver. 

change it from parameters icon/solution/Formulation>>/segregated control/solver control/change "iterative" (2 entries) to BCSLIB-EXT. 

[Anonymous]

May I get your email because the file is too big to be posted?

[Joey.X]

Could you put the whole archive model in dropbox or skydrive etc and share to my email?  

my email: xjohnh@gmail.com   

[Anonymous]

I shared the model on dropbox

[Joey.X]

have a quick look, the outlet surface can't have ioBC and pressure BC simultaneously, suggest to get rid of pressure BC and try it again. 

[Anonymous]

I am not sure of how to get rid of pressure B. Can you tell me how?

[Joey.X]

At design scenario 4, the model has veolcity BC at inlet surface,  inlet/out BC and pressure BC at outlet surface. the latter is redundant. It is suggested to delete pressure/traction BC by click "loads and constriant group", select pressure BC, right click to delete. 

[Anonymous]

Can you help me with this error. I place the new file of the part in dropbox

Autodesk (R) Simulation Steady Fluid Flow

Version 2012.00.00.0163-W64/X64 04-Mar-2011

Copyright (c) 2011, Autodesk, Inc. All rights reserved.

 ----------------------------------------------------------------

    Date & Time         : 06-20-2012  14:01:54

    Input File          : E:\Reactor.ds_data\4\ds        

    Command Line Options: -silent-x721724

    PROGRAM               VERSION: 201200000163

    Alg-win-x64.DLL       VERSION: 201200000163

    AlgConfig-win-x64.DLL VERSION: 201200000163

    Agsdb_ar-win-x64.DLL  VERSION: 201200000163

    AlgSolve.exe          VERSION: 201200000163

 ----------------------------------------------------------------

 **** Starting main program

 **** Model Unit System Settings:

      --------------------------------------------

       Unit System              : English (in)

       Force                    : lbf

       Length                   : in

       Time                     : s

       Temperature (Absolute)   : deg F (R)

       Thermal Energy           : in*lbf

       Voltage                  : V

       Current                  : A

       Electrical Resistance    : ohm

       Mass                     : lbf*s^2/in

      --------------------------------------------

 **** Memory dynamically allocated = 31042 KB (1% of physical memory)

 **** Generating coordinates

 **** Generating initial conditions

 **** Generating boundary conditions

 **** FEA information

      Model Dimension........................... =   3D model

      The number of nodes....................... =   18650

      The number of elements.................... =   56266

      The number of equations................... =   69384

 **** Segregated Scheme Data

      Select segregated scheme ................. =   T

      Solver for momentum equations ............ =   Automatic          

      Solver for pressure equations ............ =   Automatic          

      Velocity relaxation factor ............... =   7.000E-01

      Pressure relaxation factor ............... =   5.000E-01

      Inertial relaxation factor ............... =   1.000E+00

      Apply automatic adaptive parameter control =   T

      ID of Detect stagnation due to oscillation =   1

      The number of equations (U)............... =   16999

      The number of equations (V)............... =   16999

      The number of equations (W)............... =   16866

      The number of equations (P)............... =   18520

 **** Turbulence Model Data..................... =   Off

 **** Proceeding with Equal-Order Segregated Method

 **** ENTERING TIME LOOP

 Step                                        NonL. Solv. == Euclid L-2 Norm ==

 Intv  Step     Time   Percent    DT      L  Iter  Iter   R_Norm_V    R_Norm_P

    1     1  1.000E+00   0.00  1.000E+00  1          50   |R/F|u =  NaN     

 **** Error: Divergence detected in iterative solver.

             Please try sparse solver.

[Joey.X]

I have downloaded your updated model, and set the part material as air. The model is running, and the divergence error in your last post is gone. 

More suggestions/comments

- Change velocity boundary as fully constrainted in all three directions for better convergence.

- The model still has not set up any part as porous media, you can do it later by the comments in my first post in this thread. 

Good luck. 

[Anonymous]

I still got a error.

**** Error: Divergence detected in iterative solver.
Please try sparse solver.

Did you upload the new model in my dropbox?

I will send you back the model I just work with.

[Joey.X]

hi, Asif,

Sorry for the late reply. I ahve uploaded tyhe archive file back to your dropbox named as  Reactor2.ach, you can open it from SIMMP, notes that I kept the DS4 only which seems being your working one, and the result file and solver file are included, you can directly see the velocity/pressure result.And let me know for more questions.

Regards,

[Anonymous]

Hi

I can not open the file from my dropbox. Can you tell me how to open it?

thank you for all your help

[Anonymous]

When I try to open the file, it says no design scenario was found for the model.

[Joey.X]

.ach is SIMMP's zipped archive format,  you can open it using either of the methods

(a) Start SIMMP first, from file/archive/retrive

     Or directly db-click .ach file to open .ach file if you have installed SIMMP. 

(b) Rename .ach to .zip, unzip it using any utilities , open .fem file 

[Joey.X]

which SIMMP version you are using? I am using v2013, if you are usign early version, then there could be some issues . Trying method B in my previous post.

[Anonymous]

I using 2012

[Anonymous]

I am still not able to open the file