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BC: inletOutlet,buoyantpressure,and $interFields

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Old   November 27, 2012, 21:49
Default BC: inletOutlet,buoyantpressure,and $interFields
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Dongyue Li
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hi Foarmers:

I have been learning using OF for 3 months,now I am facing some tiny difficulties about BC.

I see in alpha1 dictionary, you can set
Code:
OUTLET
    {
        type            inletOutlet;
        inletValue      uniform 0;
        value           uniform 0;
    }
I interpret it as air can get in and get out, but while simulating , I find it water can get out too, so what does this mean?

in p_rgh dictionary,
Code:
walls
    {
        type            buoyantPressure;
	value		uniform 0;
    }
I dont get this buoyantPressure , ,,,some other cases set:
Code:
walls
    {
        type            fixedFluxPressure;
        value           uniform 0;
    }
what does this fixedFlusPressure mean and the difference between buoyantpressure?



also in p_rgh dictionary

Code:
outlet
    {
	type		fixedValue;
	value           $internalField;
    }
Does this $internalField mean it is calculated by the internaFields? can I just modify it to
Code:
atmosphere
    {
        type            totalPressure;
        p0              uniform 0;
        U               U;
        phi             phi;
        rho             rho;
        psi             none;
        gamma           1;
        value           uniform 0;
    }

and the k and epsilon dictionary, I know k can be caculated by 1/2*(u^2)....,but some time it cant be set this way, so I dont know how to set the value of them.....

your help is very appreciated.Thank you in advance.
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Old   November 29, 2012, 03:04
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can anyone give me a hint?
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Old   December 27, 2012, 07:41
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Hi,

please check this thread,

Questions about the inletOutlet and outletInlet boundary conditions

regards,
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Old   July 18, 2013, 06:51
Default hi you offer the site that look like not very helpful
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Quote:
Originally Posted by rebel ahmed View Post
hi you offer the site that look like not very helpful, i want to know the diference between buoyantpressure and fixedfluxpressure.
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Old   August 26, 2013, 19:54
Default buoyantpressure vs fixedfluxpressure
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Anyone knows the answer to the question in this thread?

I have a buoyantBoussinesqPimpleFoam that crashes if I use buoyantpressure , but converges perfectly if I use fixedfluxpressure. I've seen both BCs used in p_rgh. Anybody care to comment? Thanks
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Old   August 26, 2013, 19:59
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Sorry, I still dont know the difference between buoyantpressure and fixedfluxpressure.
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Old   May 28, 2014, 08:02
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Any clarity on the difference between them yet, sharonyue?
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Regards,

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Old   October 16, 2014, 03:25
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Quote:
Originally Posted by Sherlock_1812 View Post
Any clarity on the difference between them yet, sharonyue?
Hello!

Now I know that the difference between outletInlet and inletOutlet,

outletInlet:

outlet is a fixed value and inlet is zerogradient. Thats means if you set outlet value to be 0, so only 0alpha phase can get out. but any phase can get in.

inletOutlet:

vice versa.

Now I still dont know the difference between buoyantPressure and fixedFluxpressure. But looks like the first one is always used in VOF but the second one is used in two-fluid model. Im not sure.

Any comments is welcomed.
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Old   October 18, 2014, 17:06
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Quick answer - Have a look at this thread: I need explanations about fixedFluxPressure
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