CFD Online Discussion Forums

CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   Phoenics (http://www.cfd-online.com/Forums/phoenics/)
-   -   SOS! HELP! max number of cells :( (http://www.cfd-online.com/Forums/phoenics/51730-sos-help-max-number-cells.html)

Jas February 9, 2004 13:57

SOS! HELP! max number of cells :(
 
I desperately tried to work it out this problem and i really hope someone could help if you'd ever came aross the similar situations.

I have increased the max. number of cells to be used for BFC grid system, for both y and z direction. I changed the size of F-array in photon.for file where IFSIZE has been changed to a bigger value than the default setting in PHOENICS. Therefore i managed display the geometry successfully when i increased the number of cells that i used.

However, when i try to run the simulation (running the earexe.exe), the error message popped up and i cant even run the simulation. After many many many testings, I found out that it is due to the increase of these number of cells that are actually CAUSED the problem. I can only run my simulation with less number of cells.

In order to successfully run the simulation with more number of cells (say 200 in z-direction and 150 in y-direction) I really dont know what other settings i need to change again in PHOENICS v3.5.

Could anybody help.

sad, Jas


STK February 9, 2004 19:05

Re: SOS! HELP! max number of cells :(
 
I THINK WITH OUT BEING SURE (BECAUSE I HAVENT FACED THAT SITUATION) YOU HAVE TO CHANGE THE F-ARRAY INSIDE THE MAIN.F CODE THE CODE THAT EAREXE USES TO RUN THE SIMULATION. DO THE SAME CHANGES THERE AND YOU WILL RUN IT SUCCESFULLY, OF COURSE AFTER COMPILING THE MAIN.F (COMPILE EARTH)

Jas February 12, 2004 02:20

Re: SOS! HELP! max number of cells :(
 
I did modify that before, which i forgot to mention here. But it should not caused by the limitations of the number of cells, since 200 cells in both y and z directions are not a big number actually. I am thinking maybe some other reasons that may lead that... Anyway, the simulation does start when i try to increased the number of cells. When i decreased it, it works! why??

Rami February 12, 2004 04:10

Re: SOS! HELP! max number of cells :(
 
Jas,

If the problem occurs when you run EARTH, STK's suggestion seems to be the answer. Check the result file (near its beginning), where the messages concerning the available and required F-array dimensions are given. If another dimension parameter is exceeded, you should also see an appropriate message there. In addition, you may also see messages in the standard output.

Once you know what parameter is needed, fix it in main.f, compile it (using compile.bat) and build it (using bldear.bat). The resulting earexe.exe should run, and you should verify that the new F dimension appears in the result file.

I hope this helps,

Rami

Olof Liungman February 14, 2004 11:12

Re: SOS! HELP! max number of cells :(
 
Hi Jas!

Could you post the actual error message? I am not sure I understand what happens, exactly.

On Unix-systems I've noticed that there are limits on the amount of memory a given program can access, which means a program can crash even though there is sufficient physical RAM. You can change these limits though I do not remember the actual shell command right now.

Olof


All times are GMT -4. The time now is 22:21.