I have been running simulations on a car of mine but it often takes a lot of core hours. For example [https://www.simscale.com/workbench/?pid=87472876478525063&mi=run%3A16%2Csimulation%3A3&mt=SIMULATION_RUN](https://this one simulation) took me over 500 core hours and it is not even fully completed. So I was wondering if it was possible to reduce my core hours in some significant way. I cannot really make a coarser mesh around my car because it is already quite coarse. But maybe would using different results controls help or running the simulation at a lower speed (I have run simulations at lower wind speeds and while it didn’t reduce the core hours directly the simulation converged in a shorter period of time so the total core hours were reduced.).
Any help would be amazing!
Thanks!
Hi,
Here are some comments:
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Is there a particular reason for simulating the whole car instead of half of it? The cell count goes up by roughly 50% due to that
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Requesting data every 250 iterations will just increase memory requirements, potentially forcing you to use larger machines not to run into memory issues
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As far as machine size goes, usually 1 processor will handle somewhere between 500k-1M mesh cells. The closer it gets to 1M cells per core (or upwards of that) the more likely you are to run into memory issues.
If you have a mesh with 8M cells, it’s likely that you can run this with 16 cores. If you go for 8, you will likely run into trouble. The runtime does not scale 100% linearly with the number of cores, so if you use 32 cores instead of 16, you will run the simulation faster, but not 2x as fast.
As a result, usually the least amount of processors that allow you to run a study (from a memory perspective) will usually be the most cost-efficient.
You’re using 64 cores for 18M cells right now, and it’s likely that 32 would work. But again, maybe running the full model is not even necessary in the first place.
Cheers
I find running the full model is extremely helpful to visualize results. Is there any suggestions you have for reducing the number of cells in my mesh?
