how to adjust velocity in 0/u file Automatically

liwenpeng · July 17, 2020, 06:30

Hi,OPers
I'm new to Openfoam and wondering how to change parameters automatically after a successful run. I have a flow around cylinder case with constant inlet velocity which is simulated with pimpleFoam (in laminar mode). I want to increase the Reynolds number (by changing the inlet velocity after each successful run with the solver and then rerun the solver and I want to find an automatic way to do that.
I might have to run thousands of simulations, and manually modifying parameters is terrible ，so I'm wondering how it can be done in Openfoam.
many thanks

random_ran · July 17, 2020, 11:17

If your Reynolds number has a range that covers from 1 to 100000,
it's hard to auto this process. Higer Re means higher grid resolution.

People usually do discretized runs. In other words, set up cases in
advance. Then run those simulations independently.

liwenpeng · July 17, 2020, 23:48

Quote:

Originally Posted by random_ran

If your Reynolds number has a range that covers from 1 to 100000,
it's hard to auto this process. Higer Re means higher grid resolution.

People usually do discretized runs. In other words, set up cases in
advance. Then run those simulations independently.

the Reynold number will not larger than 5000.Did I need a pyfoam or install matlab in linux system to to run thousands of simulations automatically?

hxaxtma · July 18, 2020, 06:20

For changing velocity you can use uniformFixedvalue with tabulated input..
e.g.

Iteration velocity
0 1
1000 10
2000 20

And so on.

July 17, 2020, 06:30	how to adjust velocity in 0/u file Automatically	#1
liwenpeng New Member liwenpeng Join Date: Jul 2020 Posts: 11 Rep Power: 6	Hi,OPers I'm new to Openfoam and wondering how to change parameters automatically after a successful run. I have a flow around cylinder case with constant inlet velocity which is simulated with pimpleFoam (in laminar mode). I want to increase the Reynolds number (by changing the inlet velocity after each successful run with the solver and then rerun the solver and I want to find an automatic way to do that. I might have to run thousands of simulations, and manually modifying parameters is terrible ，so I'm wondering how it can be done in Openfoam. many thanks

July 17, 2020, 11:17		#2
random_ran Member Ran Join Date: Aug 2016 Posts: 69 Rep Power: 10	If your Reynolds number has a range that covers from 1 to 100000, it's hard to auto this process. Higer Re means higher grid resolution. People usually do discretized runs. In other words, set up cases in advance. Then run those simulations independently. __________________ Yours in CFD, Ran

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July 18, 2020, 06:20		#4
hxaxtma Senior Member Join Date: Jan 2014 Posts: 179 Rep Power: 12	For changing velocity you can use uniformFixedvalue with tabulated input.. e.g. Iteration velocity 0 1 1000 10 2000 20 And so on.