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Old   June 30, 2014, 17:08
Default swak4Foam and Lagrangian simulation
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Clint Bedick
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Guys, had a quick question about swak4Foam. Got it installed and working very well for specifying inlet velocity profiles, etc.

Is there any way I can use the swak4Foam utilities to specify an initial particle velocity profile (U0 in the Lagrangian cloud properties file) similar to how I use it to specify my gas phase velocity boundary condition? Ideally, I would like to set the initial particle velocity to a value that is a function of the gas velocity at that boundary and particle diameter.

If anybody has any ideas other than swak4Foam, let me know as well.

Thanks!

-Clint
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Old   July 2, 2014, 18:25
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Originally Posted by ecbmxer View Post
Guys, had a quick question about swak4Foam. Got it installed and working very well for specifying inlet velocity profiles, etc.

Is there any way I can use the swak4Foam utilities to specify an initial particle velocity profile (U0 in the Lagrangian cloud properties file) similar to how I use it to specify my gas phase velocity boundary condition? Ideally, I would like to set the initial particle velocity to a value that is a function of the gas velocity at that boundary and particle diameter.

If anybody has any ideas other than swak4Foam, let me know as well.

Thanks!

-Clint
Yep. funkySetLagrangianField. See the example case Examples/Lagrangian/parser/simplifiedSiwek (Presentation about it at http://openfoamwiki.net/staticPages/...K_again.html#/ )

This is currently a bit painful as ALL relevant fields have to be created that way.
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Old   July 3, 2014, 08:30
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Thank you for the response! I will look into the funkySetLagrangianField. Is that compatible with the native OpenFOAM cloud functions for Lagrangian simulations? I thought I recall reading that you can add Lagrangian particles to any simulation using swak4foam.

Either way, I found a work around for my problem. The main thing I wanted was the particles to be injected through a patch at the patch gas velocity (which I specify as a parabolic profile). But that is tough to do normally since you don't know where a given particle will be injected each time.

There is another injection model called patchFlowRateInjection though, which does just that. The only downside is you have to specify the injection rate in terms of a "concentration" (concentration profile of particle volume to carrier volume, non-dimensional) and "parcelConcentration" (parcels to introduce per volume flow rate, n/m3). I just kind of played with the values until I got a reasonable number of particles to inject. It would be tough to actually calculate exact injection rates since I am also using a size distribution and I don't know what size particle will be injected each time.
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Old   July 3, 2014, 16:11
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Originally Posted by ecbmxer View Post
Thank you for the response! I will look into the funkySetLagrangianField. Is that compatible with the native OpenFOAM cloud functions for Lagrangian simulations? I thought I recall reading that you can add Lagrangian particles to any simulation using swak4foam.

Either way, I found a work around for my problem. The main thing I wanted was the particles to be injected through a patch at the patch gas velocity (which I specify as a parabolic profile). But that is tough to do normally since you don't know where a given particle will be injected each time.

There is another injection model called patchFlowRateInjection though, which does just that. The only downside is you have to specify the injection rate in terms of a "concentration" (concentration profile of particle volume to carrier volume, non-dimensional) and "parcelConcentration" (parcels to introduce per volume flow rate, n/m3). I just kind of played with the values until I got a reasonable number of particles to inject. It would be tough to actually calculate exact injection rates since I am also using a size distribution and I don't know what size particle will be injected each time.
funkySetLagrangianField works with all kinds of clouds but I'm afraid in your case it won't help you much (it's good for "pretending" that a cloud is already there). What you'd need is a groovyInjector. There is no such thing. Thought about it but programming that would be weird for various reasons. Sorry
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Old   July 3, 2014, 16:25
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No problem! Like I said, using that other injection model I was able to accomplish what I wanted, to inject particles at the gas velocity for each injection location.
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Old   July 21, 2014, 03:47
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Hi Foamers,

I am really interested to understand in deepen the patchInjection. My goal is to model an injector that gives a fixed flow rate of particles through a patch. In my case it is 0.02 percentage of the total fluid volume at the inlet. The dispersed phase as fixed diameter distribution. I am using icoUncoupledKInematikParcelFoam in OpenFoam 2.3.0.

- I did not understand what exactly is "parcelPerSecond". How can I calculate it and which is the relation with the number of particles?

- What is particleBasisType?

- What is the duration parameter? How can I set it ?

- What is the flowRateProfile and what does it mean in my simulation?

The simulation should reach a "steady state" and the flow rate of the dispearsed phase injected should constant.

I appreciate any help
Thanks in advance

Marco
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Old   July 22, 2014, 17:20
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Hi Foamers,

I am really interested to understand in deepen the patchInjection. My goal is to model an injector that gives a fixed flow rate of particles through a patch. In my case it is 0.02 percentage of the total fluid volume at the inlet. The dispersed phase as fixed diameter distribution. I am using icoUncoupledKInematikParcelFoam in OpenFoam 2.3.0.

- I did not understand what exactly is "parcelPerSecond". How can I calculate it and which is the relation with the number of particles?

- What is particleBasisType?

- What is the duration parameter? How can I set it ?

- What is the flowRateProfile and what does it mean in my simulation?

The simulation should reach a "steady state" and the flow rate of the dispearsed phase injected should constant.

I appreciate any help
Thanks in advance

Marco
Spamming the same question in multiple threads doesn't raise the likelyhood of an answer. Especially if the question doesn't fit the thread at all (as it is the case here)
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Old   July 23, 2014, 01:19
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I do not think that the question does not fit the thread and I do not think that it is "spamming".
Nevertheless, I trust to an "Assistant Moderator" opinion and I will remove the post.

Regards
Marco
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Old   July 23, 2014, 16:29
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I do not think that the question does not fit the thread and I do not think that it is "spamming".
Nevertheless, I trust to an "Assistant Moderator" opinion and I will remove the post.

Regards
Marco
With "spamming" I meant: posting the same question in multiple threads (if I counted correctly 4 in the case of this question) just because the title is somewhat related to your question.

And the topic of this thread WAS very specific. Even if someone would answer your question here somebody later looking for keywords related to you question would say when looking at the search results "No. This thread is about swak&lagrangian not about the general lagrangian models. Won't look at it". It would be like putting a sheet of paper with your favourite Chilli-con-carne recipe into a vegetarian cookbook: you'll never find it there 3 years later because you're not going to look for it there.
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