Pulsed Source Term in OpenFOAM

taaresh01 · February 7, 2021, 12:51

Hello FOAMers!

I am trying to model a dimensionedScalar source term in a particular region of the mesh, which pulsates with time, i.e. this source term is a square wave which is ON for a period of t1 seconds, and then is OFF for the next t2 seconds, and so on. Let's say I want to simulate "p" pulses of this type. Basically, there is an associated frequency for this source. It also varies in space, but I think I can take care of that part. Could someone let me know how I can go about implementing this periodic (in time) source term?

PS - I am a novice at OF development at this point. Thank you in advance!

HPE · February 7, 2021, 15:17

I think you can scan the available fvOptions first. If not available, please modify the fvOption closest to your application. Function1 and PatchFunction1 for the time-variant ramp and square functions (and others) are available as well.

https://develop.openfoam.com/Develop...ources/derived

https://develop.openfoam.com/Develop...ions/Function1

Hope these can give a useful start for you.

taaresh01 · February 7, 2021, 17:32

Thank you @HPE. I'll take a look at these. I was actually able to implement it using a basic if/else structure by defining bool flags for the pulses (ON period) and gaps between pulses (OFF period). But it would be nice to see if I can use/modify some existing fvOptions functionality to do it in a better way.

Thank you!

February 7, 2021, 12:51	Pulsed Source Term in OpenFOAM	#1
taaresh01 New Member Taaresh Join Date: Nov 2017 Posts: 7 Rep Power: 8	Hello FOAMers! I am trying to model a dimensionedScalar source term in a particular region of the mesh, which pulsates with time, i.e. this source term is a square wave which is ON for a period of t1 seconds, and then is OFF for the next t2 seconds, and so on. Let's say I want to simulate "p" pulses of this type. Basically, there is an associated frequency for this source. It also varies in space, but I think I can take care of that part. Could someone let me know how I can go about implementing this periodic (in time) source term? PS - I am a novice at OF development at this point. Thank you in advance!

February 7, 2021, 15:17		#2
HPE Senior Member Herpes Free Engineer Join Date: Sep 2019 Location: The Home Under The Ground with the Lost Boys Posts: 932 Rep Power: 12	I think you can scan the available fvOptions first. If not available, please modify the fvOption closest to your application. Function1 and PatchFunction1 for the time-variant ramp and square functions (and others) are available as well. https://develop.openfoam.com/Develop...ources/derived https://develop.openfoam.com/Develop...ions/Function1 Hope these can give a useful start for you. __________________ The OpenFOAM community is the biggest contributor to OpenFOAM: User guide/Wiki-1/Wiki-2/Code guide/Code Wiki/Journal Nilsson/Guerrero/Holzinger/Holzmann/Nagy/Santos/Nozaki/Jasak/Primer Governance Bugs/Features: OpenFOAM (ESI-OpenCFD-Trademark) Bugs/Features: FOAM-Extend (Wikki-FSB) Bugs: OpenFOAM.org How to create a MWE New: Forkable OpenFOAM mirror

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February 7, 2021, 17:32		#3
taaresh01 New Member Taaresh Join Date: Nov 2017 Posts: 7 Rep Power: 8	Thank you @HPE. I'll take a look at these. I was actually able to implement it using a basic if/else structure by defining bool flags for the pulses (ON period) and gaps between pulses (OFF period). But it would be nice to see if I can use/modify some existing fvOptions functionality to do it in a better way. Thank you!