Memory Error whilst trying to simulation


#1

Hey everyone,

Every time I try to run my simulation I get the following error message:

The job execution was aborted. A possible cause is that not enough memory was available. In this case, selecting a larger instance or using a coarser mesh should resolve the issue.

My mesh is already relatively coarse for a CFD/HT simulation and I’m not too sure what it means by instances… :confused:

Cheers,

Akshay


#2

Hi @AkshayMalde,

is it happening in a public project? Happy to take a look! Could you provide the link to it?

Thanks,

David


#3

Hi David,

Yeah, it’s a public project.
Here’s the link:

https://www.simscale.com/workbench/?pid=453849643537966148#tab_1-0

In the Simulation Designer, it’s Run 1 under the Turbulent Flow simulation.

Thanks!


#4

Hi Akshay,

alright - so I just had a quick look, but what I can definitely say is that the operations log message is miss-leading (already known - an improved error reporting for this is underway). The problem is not that the machine is running out of memory - in fact, your core count is not efficient. With 400k cells, an 8 core machine is more than enough.

The problem seems to be numerical instability. I didn’t find anything obvious in the solver log message. So the most obvious question would be: 10m/s inlet with a 5cm geometry - quite some speed, is that intended? The next question would be how you came up with the values for k and omega? Did you use some correlation / hand calculation? That could be one reason for the instability and the next place to look would be the numerical schemes.

@gholami has got more experience with CHT. Babak, anything obvious to you?

Best,

David


#5

Hey David,

As for the speed, I was trying to make it a pretty turbulent flow, I calculated that with 10 m/s the flow has a Re number of 7768 for that geometry.
With regards to the k and omega values I just based them of previous turbulent flow simulations, hence I’m sure they’re way off… haha
Same with the numerical schemes.

Thanks,

Akshay


#6

Hi Akshay, seems that I missed the previous Run1. This one went through though. Are results as you expected?


#7

Hey,

Yeah, I worked on it a bit more and realised that I had mistakenly put in one of the parameters wrong. After I corrected it I got results.
Looking at the results, they do make sense, hence they are what I expected.

Thanks,

Akshay