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Computation time in Acoustic module

Posted 25 mar 2022, 02:24 GMT-4 Acoustics & Vibrations, Computational Fluid Dynamics (CFD) Version 6.0 1 Reply

Deepak Kumar E
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Hello, can someone help me the know average computation time required to run a 3D acoustic modelling of a closed chamber.

1 Reply Last Post 28 mar 2022, 14:58 GMT-4
Jeff Hiller COMSOL Employee

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Posted: 3 years ago 28 mar 2022, 14:58 GMT-4
Updated: 3 years ago 29 mar 2022, 08:42 GMT-4

Hello Deepak,

For models in the Application Libraries, we provide typical computational times, see the attached screenshot for one example from the Acoustics Module. This could help you get a sense of what computational times to expect for various models on an ordinary PC. To see the machine that was used for one of those tests, hover over the computation time in the Application Libraries window and the machine information will be displayed in a tooltip message. BTW, at 6.1 we plan on also making that tooltip show how much memory was used to solve the problem).

With that said, unfortunately it is not possible to give a general answer to your question: computation times can vary dramatically with the model and with the hardware you're working with, with those two effects being interrelated. To illustrate this point: say, you've run a particular acoustics model at one frequency with a mesh that was just fine enough to capture the wavelength and give you accurate results, but now you want to solve the same model at twice that frequency. You'll need a mesh that's twice as fine in all three directions, so the new model will have about 8 times the number of dofs (I am assuming here that you are using one of the physics interfaces that uses a finite element approach. Please note that COMSOL also implements boundary element methods and ray tracing methods in the Acoustics Module). If the model at the lower frequency used most of your RAM, the model at the higher frequency won't fit in RAM; if the solver has to use your (slow-access) hard drive, solution time will greatly increase. On the related topic of memory usage, this blog post is a good read.

Best,

Jeff

-------------------
Jeff Hiller
Hello Deepak, For models in the Application Libraries, we provide typical computational times, see the attached screenshot for one example from the Acoustics Module. This could help you get a sense of what computational times to expect for various models on an ordinary PC. To see the machine that was used for one of those tests, hover over the computation time in the Application Libraries window and the machine information will be displayed in a tooltip message. BTW, at 6.1 we plan on also making that tooltip show how much memory was used to solve the problem). With that said, unfortunately it is not possible to give a general answer to your question: computation times can vary dramatically with the model and with the hardware you're working with, with those two effects being interrelated. To illustrate this point: say, you've run a particular acoustics model at one frequency with a mesh that was just fine enough to capture the wavelength and give you accurate results, but now you want to solve the same model at twice that frequency. You'll need a mesh that's twice as fine in all three directions, so the new model will have about 8 times the number of dofs (I am assuming here that you are using one of the physics interfaces that uses a finite element approach. Please note that COMSOL also implements boundary element methods and ray tracing methods in the Acoustics Module). If the model at the lower frequency used most of your RAM, the model at the higher frequency won't fit in RAM; if the solver has to use your (slow-access) hard drive, solution time will greatly increase. On the related topic of memory usage, [this blog post](https://www.comsol.com/blogs/much-memory-needed-solve-large-comsol-models/) is a good read. Best, Jeff

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