intro story D-Flow FM

 

D-Flow Flexible Mesh

D-Flow Flexible Mesh (D-Flow FM) is the new software engine for hydrodynamical simulations on unstructured grids in 1D-2D-3D. Together with the familiar curvilinear meshes from Delft3D 4, the unstructured grid can consist of triangles, pentagons (etc.) and 1D channel networks, all in one single mesh. It combines proven technology from the hydrodynamic engines of Delft3D 4 and SOBEK 2 and adds flexible administration, resulting in:

  • Easier 1D-2D-3D model coupling, intuitive setup of boundary conditions and meteorological forcings (amongst others).
  • More flexible 2D gridding in delta regions, river junctions, harbours, intertidal flats and more.
  • High performance by smart use of multicore architectures, and grid computing clusters.
An overview of the current developments can be found here.
 
The D-Flow FM - team would be delighted if you would participate in discussions on the generation of meshes, the specification of boundary conditions, the running of computations, and all kinds of other relevant topics. Feel free to share your smart questions and/or brilliant solutions! 

 

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We have launched a new website (still under construction so expect continuous improvements) and a new forum dedicated to Delft3D Flexible Mesh.

Please follow this link to the new forum: 
/web/delft3dfm/forum

Post your questions, issues, suggestions, difficulties related to our Delft3D Flexible Mesh Suite on the new forum.

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** PLEASE TAG YOUR POST! **

 

 

Sub groups
D-Flow Flexible Mesh
DELWAQ
Cohesive sediments & muddy systems

 


Message Boards

RE: Discontinuities in the erosion/sedimentation pattern

FM
florian MONETTI, modified 5 Years ago.

Discontinuities in the erosion/sedimentation pattern

Youngling Posts: 21 Join Date: 3/12/13 Recent Posts
Hi,
I working on the sediment dynamics around a breakwater in a harbour.
I have some issues witht the erosion pattern outside the breakwater tip.
As you can see on the figure, there are some very strange discontinuities. I have tried to play a lot with the different parameters without removing the problem.
Do you have an idea of what happen?
I think its coming from the refraction (waves are coming from west). Maybe a phase problem. I have no diffraction in the model. No wind and just tidal current. All hydrodynamic patterns looks good.
I didn't find the wao to solve it...

Cheers,

Florian
Qinghua Ye, modified 5 Years ago.

RE: Discontinuities in the erosion/sedimentation pattern

Jedi Council Member Posts: 612 Join Date: 3/2/11 Recent Posts
Hi, Florian,

I suppose your model is a 3d model?

Greetings,

Qinghua
FM
florian MONETTI, modified 5 Years ago.

RE: Discontinuities in the erosion/sedimentation pattern

Youngling Posts: 21 Join Date: 3/12/13 Recent Posts
Sorry for the lack of information.
No, it's a depth average model with depths in the range 0 - 30m.
As I said, I have tried a lot of different configurations.
I can reduce this problem with the sus, bed, susw and bedw paramters, but It's just because I reduce the sediment transport.
The problem is still existing.
It's very strange because it's local, in the refraction zone.
I would like to know if you had this kind of discontinuities before.
I will work more on the friction parameter to see if I can solve the issue.

Regards,

Florian
Qinghua Ye, modified 5 Years ago.

RE: Discontinuities in the erosion/sedimentation pattern

Jedi Council Member Posts: 612 Join Date: 3/2/11 Recent Posts
Hi Florian,

And the sediment transport formula is VR93? and what kind of sediment(s) is included in the model?

Regards,

Qinghua
FM
florian MONETTI, modified 5 Years ago.

RE: Discontinuities in the erosion/sedimentation pattern

Youngling Posts: 21 Join Date: 3/12/13 Recent Posts
The sediment formulation is Van Rijn 2004 (IFORM -2).
I tried with SOulsby/Van Rijn. It gives the same issue.
I am including just one class of sediment for this run (sand: 220 microns, Density 2850 kg/m3).
It is not my first study with Delft3D and its the first time that I see this kind of discontinuities.
It looks like a problem of phase or wave reflexion but there is no reason for that.

Florian
Qinghua Ye, modified 5 Years ago.

RE: Discontinuities in the erosion/sedimentation pattern

Jedi Council Member Posts: 612 Join Date: 3/2/11 Recent Posts
Hi Florian,

I am a little bit curious now. Can you share the input with us?

Have a nice weekend!

Qinghua
FM
florian MONETTI, modified 5 Years ago.

RE: Discontinuities in the erosion/sedimentation pattern

Youngling Posts: 21 Join Date: 3/12/13 Recent Posts
Hi Qinghua,

I have found the solution but not really the reason of the issue yet.
The solution is to use a Soulsby Van Rijn sediment formulation.
For a reason, Van Rijn 1993 and 2004 doesn't work.

I hope to put more feedback as soon as possible when I have time.
I will investigate this issue. It's really weird and interesting.

Thank you for your time Qinghua.

Best regards,

Florian

PS: I add differences between two simulations