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-   -   Simulation the flow of river by OpenFoam (http://www.cfd-online.com/Forums/openfoam/83074-simulation-flow-river-openfoam.html)

 fuji December 14, 2010 01:34

Simulation the flow of river by OpenFoam

Dear all

I want to simulate the 3D steady state flow in river (about 2km) based on about 1000 field -surveyed point defining the bathymetry.
The boundary inlet is the water level.
Could you help me to do it.

Thank you very much.
Fuji

 Bernhard December 14, 2010 03:38

What information do you want to obtain using the simulation?

 Cyp December 14, 2010 04:29

There is a Shallow water solver called shallowWaterFoam (you can find it in the incompressible directory). I never try it but I think it is a good start to your problem.

Shallow water equations are the classical way to simulate flow in the case where the horizontal length scale is much greater than the vertical length scale. The shallow water equations are derived from depth-integrating the Navier-Stokes equations. In these equations, the water level is a variable of the system.

Regards,
Cyp

 fuji December 15, 2010 02:24

Boundary: how do i input the data for it (special temporal variation of water elevation boundary)
In blockmesh file how to input all of blocks

blocks
(
hex (0 1 5 4 16 17 21 20) (50 4 1) simpleGrading (1 1 1)
hex (2 3 7 6 18 19 23 22) (50 4 1) simpleGrading (1 1 1)
hex (4 5 9 8 20 21 25 24) (50 8 1) simpleGrading (1 1 1)
hex (5 6 10 9 21 22 26 25) (20 8 1) simpleGrading (1 1 1)
hex (6 7 11 10 22 23 27 26) (50 8 1) simpleGrading (1 1 1)
hex (8 9 13 12 24 25 29 28) (50 8 1) simpleGrading (1 1 1)
hex (9 10 14 13 25 26 30 29) (20 8 1) simpleGrading (1 1 1)
hex (10 11 15 14 26 27 31 30) (50 8 1) simpleGrading (1 1 1)
);

edges
(
);

patches
(
patch inlet
(
(0 16 20 4)
(4 20 24 8)
)
patch outlet
(
(3 19 23 7)
(7 23 27 11)
)
patch lowerWall
(
(0 1 17 16)
(1 5 21 17)
(5 6 22 21)
(2 6 22 18)
(2 3 19 18)
)
patch atmosphere
(
(12 13 29 28)
(13 14 30 29)
(14 15 31 30)
(8 24 28 12)
(11 27 31 15)
)

because i have 1000 field -surveyed point defining the bathymetry along 2km river.
all pacth

.....
About shallowWaterFoam i think it has not solved my problem because
I want to simulate the 3D steady state flow in river (about 2km) based on about 1000 field -surveyed point defining the bathymetry. and than i will simulate the secdiment transport in the river. So i must use 3D full.

Thank you very much.
Best regards

Fuji

 deniggo December 15, 2010 03:23

Hello Fuji,
I'm working on a same problem, river flow over theoretical as well as measured bedforms. I found a way to create a mesh by using Matlab->Blender->SnappyHexMesh. Maybe it's not the easiest way, but it works and the results a good.
I use Matlab with a stl-file add-on and create stl files for every boundary wall (bedform, inlet, outlet, top, sidewalls). These stl files I merge in Blender and check the face orientation (all should show outside). Afterwards, I use snappyHexMesh to create a mesh.

I'm not sure if OF can handle sediment transport?!

Btw, which method did you use to measure 1000 survey points?

Nico

 fuji December 19, 2010 23:43

Thank you very much Nico

it is an excellent idea but I do not know how to use matlap.
Is there other way to enter the input data (e.g. temporal variation of water elevation boundary) ?

If I now study matlap, how long can I use matlap?

Thank you very much
Best regards
Fuji

 deniggo December 20, 2010 04:17

Hi Fuji,
I think at first you need a mesh of your domain, including your bedform, and all other walls... inlet, outlet. Afterwards you can define a temporal water elevation bc at the inlet. I use groovyBC (http://openfoamwiki.net/index.php/Contrib_groovyBC) for this in interFoam (2-phase flow). But, I think there are many other possibilities.

For creation of your bedform, I'm sure you can also use some import functions of CAD-Software. That would make more sense, if you want to use real measured data. But I didn't try it up to now, so that would be interesting for me as well.

Hope that helps,

Nico

 rob3rt 0ng December 22, 2010 00:15

Hi All,

Do you know where can I find the proper description of what shallowWaterFoam does and that sort of thing?

And is it possible to incorporate this with irradiance (attenuating of irradiance with respect to the water depth)?

Kind Regards,
Robert

 fuji December 22, 2010 02:17

Thanks a lot Nico,
I will try to use groovyBC.

Best Regards
Fuji

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