Can someone check my BCs for p & U for a 3D aerofoil simulation, please?

pizzaspinate · February 18, 2015, 14:16

Hi FOAMers,

I try to simulate a wing flying in the air using potentialFoam (I assume I have to use it if I want to run a simple Euler run?!). I did have a look at the tutorials for the motorbike and 2dmoving wing in order to get the BCs right.
However I am still not entirely sure about the BCs (see attachment) in the 0/p and 0/U file as the results I am getting are funny. Especially for p which ranges from 0 to 1e-16.

Hope someone can help me out.

tomf · February 19, 2015, 05:10

Hi,

I cannot see anything weird with your boundary conditions, so I guess you ran potentialFoam without the -writep option, which only outputs a velocity field. Rerun you potentialFoam as:

Code:

$> potentialFoam - writep

You will than also have a pressure distribution.

Just make sure you copy your 0 folder to 0.org, so you still have all the original files.

Regards,
Tom

pizzaspinate · February 19, 2015, 09:13

Hi Tom,
thank you for the quick reply!
I have done what you told me but the results seem still weird.
I have attached a screen shot of my p "distribution".

tomf · February 19, 2015, 09:51

Hi what is the output from the solver?

pizzaspinate · February 19, 2015, 10:15

Hi
for p I get as result:

Code:

/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  2.3.0                                 |
|   \\  /    A nd           | Web:      www.OpenFOAM.org                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       volScalarField;
    location    "0";
    object      p;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions      [0 2 -2 0 0 0 0];

internalField   nonuniform List<scalar> 
4528698
(
62.2165
59.0258
55.8351
52.6444
49.4538
46.2632
43.0726
39.882
36.6914
33.5008
30.3102
27.1196
23.9291
20.7385
17.548
14.3574
11.1669
7.97634
4.78581
1.59527
62.2165
59.0258
55.8351
52.6444
49.4538
46.2632
43.0726
39.882
36.6914
33.5008
30.3102
27.1196
23.9291
20.7385
17.548
14.3574
11.1669
7.97634
4.78581
1.59527
62.2165
59.0258
55.8351
52.6444
49.4538
46.2632
43.0725
39.8819
36.6914
33.5008
30.3102
27.1196
23.9291
20.7385
17.548
14.3574
11.1669
7.97634
4.78581
1.59527
62.2164
59.0258
55.8351
52.6444
49.4538
46.2632
43.0725
39.8819
36.6913
33.5008
30.3102
27.1196
23.9291
...
...
...

So they are much bigger than 1e-17

tomf · February 19, 2015, 10:21

Did you open the ParaView screen before running the case? Than you should refresh the data in ParaView (via properties of foam.foam) and than rescale to the full range (via your clip).

pizzaspinate · February 19, 2015, 10:45

I have created a foam.foam file which I always open up after I have run a simulation. Than I close it again and run another one. I tried to refresh it but it doesn't change anything :-/

tomf · February 19, 2015, 10:55

In ParaView can you select the cell values instead of the point values?

You could try to decompose the case and open the decomposed case in ParaView, but it should not be necessary. If that does not work, maybe you can put the data somewhere available to other so we can have a look ourselves.

Regards,
Tom

February 19, 2015, 05:10		#2
tomf Senior Member Tom Fahner Join Date: Mar 2009 Location: Breda, Netherlands Posts: 646 Rep Power: 32	Hi, I cannot see anything weird with your boundary conditions, so I guess you ran potentialFoam without the -writep option, which only outputs a velocity field. Rerun you potentialFoam as: Code: $> potentialFoam - writep You will than also have a pressure distribution. Just make sure you copy your 0 folder to 0.org, so you still have all the original files. Regards, Tom

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February 19, 2015, 09:51		#4
tomf Senior Member Tom Fahner Join Date: Mar 2009 Location: Breda, Netherlands Posts: 646 Rep Power: 32	Hi what is the output from the solver?

February 19, 2015, 10:21		#6
tomf Senior Member Tom Fahner Join Date: Mar 2009 Location: Breda, Netherlands Posts: 646 Rep Power: 32	Did you open the ParaView screen before running the case? Than you should refresh the data in ParaView (via properties of foam.foam) and than rescale to the full range (via your clip).

February 19, 2015, 10:45		#7
pizzaspinate Member Join Date: Dec 2012 Posts: 81 Rep Power: 13	I have created a foam.foam file which I always open up after I have run a simulation. Than I close it again and run another one. I tried to refresh it but it doesn't change anything :-/

February 19, 2015, 10:55		#8
tomf Senior Member Tom Fahner Join Date: Mar 2009 Location: Breda, Netherlands Posts: 646 Rep Power: 32	In ParaView can you select the cell values instead of the point values? You could try to decompose the case and open the decomposed case in ParaView, but it should not be necessary. If that does not work, maybe you can put the data somewhere available to other so we can have a look ourselves. Regards, Tom