OpenFoam vs. Fluent outputs

saeed jamshidi · January 29, 2024, 10:34

Hello,

I have a question regarding performance of openfoam and fluent in simulating of fluid flow. Why these tools give us different time scales?!
For instance, consider laminar flow over a cylinder at Re=100; simulation reaches to the consistency after 200 seconds by openfoam, whereas it is 20 seconds for the same case by fluent!

Regards

Tobermory · January 29, 2024, 12:04

... because you set the simulations up differently. They are both solving the same physics.

saeed jamshidi · January 29, 2024, 13:07

Tobermory، thank for the reply.
Your response doesn't deliver any information on to me😅
Would you like to go a little bit in details?!

Tobermory · January 29, 2024, 13:11

Haha - well, to be fair, you didn't supply any details either! And also

1. what do you mean by "reaches to the consistency"
2. are the times you quote simulation times or wall-clock times?

There are then countless questions that follow on: what numerical schemes did you employ? are the boundary conditions and mesh identical? steady state or transient? if transient, are the time steps the same? etc etc etc.

For us to help, you need to narrow down your question.

saeed jamshidi · January 29, 2024, 13:17

Yeap, you are right 👍.
All of the conditions are similar, numerical scheme, solver and it is transient problem. Actually, a simple case, laminar 2D flow past a cylinder with the same mesh.

I'v just noticed about significant difference between time scale in openfoam and fluent.

Best

January 29, 2024, 10:34	OpenFoam vs. Fluent outputs	#1
saeed jamshidi Senior Member Saeed Jamshidi Join Date: Aug 2019 Posts: 214 Rep Power: 8	Hello, I have a question regarding performance of openfoam and fluent in simulating of fluid flow. Why these tools give us different time scales?! For instance, consider laminar flow over a cylinder at Re=100; simulation reaches to the consistency after 200 seconds by openfoam, whereas it is 20 seconds for the same case by fluent! Regards

January 29, 2024, 13:07		#3
saeed jamshidi Senior Member Saeed Jamshidi Join Date: Aug 2019 Posts: 214 Rep Power: 8	Tobermory، thank for the reply. Your response doesn't deliver any information on to me😅 Would you like to go a little bit in details?! Tobermory likes this.

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January 29, 2024, 12:04		#2
Tobermory Senior Member Join Date: Apr 2020 Location: UK Posts: 736 Rep Power: 14	... because you set the simulations up differently. They are both solving the same physics.

January 29, 2024, 13:11		#4
Tobermory Senior Member Join Date: Apr 2020 Location: UK Posts: 736 Rep Power: 14	Haha - well, to be fair, you didn't supply any details either! And also 1. what do you mean by "reaches to the consistency" 2. are the times you quote simulation times or wall-clock times? There are then countless questions that follow on: what numerical schemes did you employ? are the boundary conditions and mesh identical? steady state or transient? if transient, are the time steps the same? etc etc etc. For us to help, you need to narrow down your question.

January 29, 2024, 13:17		#5
saeed jamshidi Senior Member Saeed Jamshidi Join Date: Aug 2019 Posts: 214 Rep Power: 8	Yeap, you are right 👍. All of the conditions are similar, numerical scheme, solver and it is transient problem. Actually, a simple case, laminar 2D flow past a cylinder with the same mesh. I'v just noticed about significant difference between time scale in openfoam and fluent. Best