Too long iteration time in parallel processing!

amin.z · August 2, 2014, 15:27

Hi
I need your exprience!

I use fluent 6.3 and I have a 3D domain with 6,500,000 elements!
For my problem, I'm activing energy equ. and k-epsilon model and I'm using air as ideal gas as material!
Note that My domain also have 2 mesh interfaces!

I run fluent as parallel in this system:
Windows 7
Ram 12 Gb
8 parallel CPUs with frequency 2.9 GHz!

When Iterations started, the time for 10 iterations is about 15 mins!

Is this normal?
And is this sentence correct:
"If I increase pc Ram, the solution time will decrease"

Any idea absolutly will be benefit!
Best regards!

ghost82 · August 4, 2014, 03:00

How much ram are you using when iterating? Check performances in windows task manager.

amin.z · August 4, 2014, 03:05

Quote:

Originally Posted by ghost82

How much ram are you using when iterating? Check performances in windows task manager.

Hey!
Tnx for your reply!

More than 11.5 Gb

ghost82 · August 4, 2014, 10:37

Probably your ram is full and the system is using the swap space on your hdd, which is much slower.
You should increase the total amount of ram.

Daniele

amin.z · August 4, 2014, 10:51

Quote:

Originally Posted by ghost82

Probably your ram is full and the system is using the swap space on your hdd, which is much slower.
You should increase the total amount of ram.

Daniele

Oh! maybe! Probably you're right!
when I tried this mesh with a PC with quad core CPU & 4 Gb ram, I faced "low memory" error!

Do you have any idea to increasing solution time with current computer?

ghost82 · August 4, 2014, 11:28

Ram speed and amount is very important in cfd simulations, maybe the most important component.
If your model doesn't fit in the current amount of ram, the only thing to do is to expand it or to decrease the total amount of cells to try to fit the model into your current setup.

Daniele

amin.z · August 4, 2014, 11:31

Dear Daniele!
Thank you very much!

August 2, 2014, 15:27	Too long iteration time in parallel processing!	#1
amin.z Senior Member Amin Join Date: Oct 2013 Location: Germany Posts: 397 Rep Power: 14	Hi I need your exprience! I use fluent 6.3 and I have a 3D domain with 6,500,000 elements! For my problem, I'm activing energy equ. and k-epsilon model and I'm using air as ideal gas as material! Note that My domain also have 2 mesh interfaces! I run fluent as parallel in this system: Windows 7 Ram 12 Gb 8 parallel CPUs with frequency 2.9 GHz! When Iterations started, the time for 10 iterations is about 15 mins! Is this normal? And is this sentence correct: "If I increase pc Ram, the solution time will decrease" Any idea absolutly will be benefit! Best regards!

August 4, 2014, 10:37		#4
ghost82 Senior Member Rick Join Date: Oct 2010 Posts: 1,016 Rep Power: 26	Probably your ram is full and the system is using the swap space on your hdd, which is much slower. You should increase the total amount of ram. Daniele amin.z likes this.

August 4, 2014, 11:28		#6
ghost82 Senior Member Rick Join Date: Oct 2010 Posts: 1,016 Rep Power: 26	Ram speed and amount is very important in cfd simulations, maybe the most important component. If your model doesn't fit in the current amount of ram, the only thing to do is to expand it or to decrease the total amount of cells to try to fit the model into your current setup. Daniele amin.z likes this.

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