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

Restart from Map

CE
Christopher Esposito, modified 6 Years ago.

Restart from Map

Padawan Posts: 35 Join Date: 10/16/12 Recent Posts
Hi All,

I'm having some trouble restarting from map files in my current model. I'm not sure what's going on, I haven't had this problem in the past, but now when I restart from a map, the system reinterpolates the surface, and changes some of the topography. You can see this in the attached image. The bottom figure is the map that I am starting from, and the top figure is the start of the new run. Since the dates are the same, the topography should be identical, but you can see that the channels in the start o the new run are much wider than they had been.

Do you know what's going on here?

I'm also attaching my run files, in case that helps.

-Chris
CE
Christopher Esposito, modified 6 Years ago.

RE: Restart from Map

Padawan Posts: 35 Join Date: 10/16/12 Recent Posts
Bump!

Anybody have any ideas on this? It's actually becoming a major problem for me, because it means that if a long term simulation crashes then I have to restart from the beginning with a smaller timestep andhope for the best.

The problem may not be entirely clear until you open the .png file. The preview shown in the post doesn't give an idea for the severity of the issue.


-Chris
Adri Mourits, modified 6 Years ago.

RE: Restart from Map

Yoda Posts: 1224 Join Date: 1/3/11 Recent Posts
Hi Christopher,

First I thought it has to do with drying/flooding. But according to your description that is not the case here. It really has to do with the bed level being changed when restarting, right?

I'll have to discuss it with my colleagues.

Regards,

Adri
CE
Christopher Esposito, modified 6 Years ago.

RE: Restart from Map

Padawan Posts: 35 Join Date: 10/16/12 Recent Posts
Thanks Adri,

It is actually changing the bed level on restarting from the map file. I thought at first that I was tracking too many underlayers, but I still had the problem when I reduced them. I've also gotten a suggestion that running the model with "Depth Specified at Grid Cell Centers" might alleviate the problem, but I haven't been able to try that yet.

If you have a speedy internet connection, you can see the problem in action by downloading one of my model runs from this dropbox link:

https://www.dropbox.com/s/c8miw14zcwzu2nw/postD_forAdri.zip

It's about 350MB, zipped. If you try to start postD02 from the last map of postD01, you might be able to see what's going on more clearly.

Thanks for your help.

-Chris
CE
Christopher Esposito, modified 6 Years ago.

RE: Restart from Map

Padawan Posts: 35 Join Date: 10/16/12 Recent Posts
Adri,

Running the models with Depth Specified at Cell Centers seems to be solving the problem. I'm surprised, becasue I've never noticed this issue before, and i think that most of my models have been run with Depth Specified at Cell Corners, but at least this seems to be a workaround for the moment.

-Chris
Bert Jagers, modified 6 Years ago.

RE: Restart from Map

Jedi Knight Posts: 201 Join Date: 12/22/10 Recent Posts
Hi Chris,

The morphology module updates the bed levels in the cell centres. The trim-file also contains the time series of bed levels at cell centres. Upon restart from a trim-file, the dpsopt flag is automatically switched to DP. The tri-diag.postD02-001 file contains a line

*** WARNING DPSOPT value reset to DP because of restart

to indicate that. So, why doesn't it work?

It seems that this feature doesn't work with parallel computing. Although the flag is changed for the first partition, the other three tri-diag files don't include such line. These partitions assume that the bed level has been specified at the corner points and use MAX to "interpolate" the data to cell centre. You may observe that in 1/4 of the domain the restart is done correctly. By manually switching the dpsopt in the mdf file to DP, you make sure that all partitions use the correct flag.

Now we know what caused the problem, we'll fix it.

Cheers,

Bert
CR
Chunping Ren, modified 2 Years ago.

RE: Restart from Map

Youngling Posts: 13 Join Date: 10/12/15 Recent Posts
I am a new user delft 3d. I have beeing try to set up a river model. I really need your help. Could you tell me how to restart model from map files?
Thank you very much!!
Best regards.
Chunping ren
Adri Mourits, modified 2 Years ago.

RE: Restart from Map

Yoda Posts: 1224 Join Date: 1/3/11 Recent Posts
Hi Chunping,

The GUI will help you to set up a model including restarting. See the Delft3D-FLOW User Manual, section 4.5.5 Initial conditions.

Regards,

Adri
CR
Chunping Ren, modified 2 Years ago.

RE: Restart from Map

Youngling Posts: 13 Join Date: 10/12/15 Recent Posts
Hi Adri,
I got it! Thank you very much!
Chunping