Hi Amin,

About the post #19:
potentialFoam writes the field(s) in the same folder. It's designed this way because it's one of the simplest solvers there are... it simply solves the perfect potential flow. It even barely iterates... therefore, the developers probably thought that it wasn't necessary to save the results in a new time/instance snapshot.

About post #20:
I think the problem is that you didn't run the script Allrun:
Best regards,
Bruno

Good Day Romant,

As per your instructions, I made folder name called david, Again I am trying to run cylinder in OF 2.1. but I got the same error, kindly help me and also I set Enabling allowSystemOperations 0 to 1 and I also I changed U

I follow these steps from Allrun script
After blockMesh, Instead of streamFunction, I run potentialFoam, I got error like this,

Hi David,

I'll address one topic at a time:

1. The way to a successful execution of the tutorial "basic/potentialFoam/cylinder" is as follows:
   1. Make sure you have a personal copy of the OpenFOAM tutorials, as explained in the OpenFOAM User Guide: http://www.openfoam.org/docs/user/tu...s.php#x4-30002
      
      Quote:

      Code: mkdir -p $FOAM_RUN cp -r $FOAM_TUTORIALS $FOAM_RUN

   2. Then go into the respective tutorial case, by running:
      
      Code:

      ---

      cd $FOAM_RUN
cd tutorials/basic/potentialFoam/cylinder

      ---

   3. There are a few ways to ensure that the flag "allowSystemOperations" is set to 1, as explained here: http://openfoamwiki.net/index.php/Ho...in_debug_flags
      But to keep thing simple, run the following commands:
      
      Code:

      ---

      mkdir -p ~/.OpenFOAM/$WM_PROJECT_VERSION
cp $WM_PROJECT_DIR/etc/controlDict ~/.OpenFOAM/$WM_PROJECT_VERSION/controlDict

      ---

   4. Now, to run this tutorial case, you simply need to run:
      
      Code:

      ---

      ./Allrun

      ---

   5. To reset the tutorial case to the point before Allrun was executed, run:
      
      Code:

      ---

      ./Allclean

      ---

2. Now, once the Allrun has finished executing, it will have created 3 log files:
   
   Code:

   ---

   log.blockMesh
log.potentialFoam
log.streamFunction

   ---

   Each one is respective to the output of each major application that was executed.
3. If you want to executed these commands manually, instead of running Allrun, then these should do the trick:
   
   Code:

   ---

   #For enabling the allowSystemOperations variable
sed -i -e s/"\(allowSystemOperations[ \t]*\)\([0-9]\);"/"\1 1;"/g ~/.OpenFOAM/$WM_PROJECT_VERSION/controlDict

#copy the initial files, in case you don't have them yet
cp -r 0.org 0

#generate the mesh
blockMesh

#run the solver
potentialFoam

#calculate the stream function
streamFunction

   ---

4. As for results:
   1. The "0/U" file should now have the internal potential flow in m/s
   2. The "0/p" file is not modified, unless you run potentialFoam with the option "-writep":
      
      Code:

      ---

      potentialFoam -writep

      ---

   3. The "0/streamFunction" file is the result from the streamFunction utility.
   4. The files "0/UA" and "0/error" are respectively: the analytical flow result and "error=(U-UA)/mag(UA)". These are calculated by the function object "difference" that is inside the file "system/controlDict".
   5. There is no other time folder, because potentialFoam is an extremely basic folder that loads and saves the results to the same time folder.

Now, regarding the change you said you made to the "0/U" file: the code you posted is identical to the original code that is in the file "0.org/U" and I've used OpenFOAM 2.1.0 installed from the Deb package and it ran without any problems.
So, I'm not able to reproduce the same error, but the error seems familiar to me, so perhaps I have modified my OpenFOAM 2.1.0 installation...
Either way, I advise you to upgrade to either OpenFOAM 2.1.1 ( http://www.openfoam.org/archive/2.1....oad/ubuntu.php ) or even to 2.2.1 ( http://www.openfoam.org/download/ubuntu.php ). As you can see from these links, I'm assuming you are using Ubuntu.


edit: Also study in the Programmers Guide - http://foam.sourceforge.net/docs/Gui...mmersGuide.pdf - start reading from the section 3.1 "low around a cylinder"

Best regards,
Bruno

Million Thanks Bruno, I check blockMesh it works fine. I can understand up to step 4.4 , the results are below

4.5 What it mean(there is no time folder) how I can see the results in paraview. whether I have to type foamToVTK?

Hi David,

I'm guessing that you haven't studied the first tutorial in the User Guide: http://www.openfoam.org/docs/user/cavity.php#x5-40002.1
There you'll find instructions on how to use ParaView with OpenFOAM.

What I meant by "no other time folders" is that other solvers usually create more time snapshots, while potentialFoam does not. For example, the first run of icoFoam in the cavity tutorial (on that link above), will create 5 new time folders:
Best regards,
Bruno

Many Apologize Bruno I get confused, I thought Potential Foam create more snapshots,thanks for response and information.

Kindly see my another post in this link [ http://www.cfd-online.com/Forums/ope...tml#post446556 ] I edit blockMeshDict, kindly give your suggestion.