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! 

 

=======================================================
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.

=======================================================

** PLEASE TAG YOUR POST! **

 

 

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

 


Message Boards

Delft3D-FLOW: *** ERROR Deltas > water depth in TRATUR

RM
Ruairi MacIver, modified 5 Years ago.

Delft3D-FLOW: *** ERROR Deltas > water depth in TRATUR

Padawan Posts: 45 Join Date: 5/1/13 Recent Posts
Can anyone shed light on the cause and the implications of the following error?
*** ERROR Deltas > water depth in TRATUR

It appears many times in a couple FLOW-WAVE simulation where the FLOW model uses Domain Decomposition to couple a 2D domain and a 3D domain and the error occurs in the 3D domain.

Thanks
Ruairi
Adri Mourits, modified 5 Years ago.

RE: Delft3D-FLOW: *** ERROR Deltas > water depth in TRATUR (Answer)

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

"Deltas" is an internally computed boundary layer thickness where wave induced turbulence are taken into account. Deltas should be smaller than the water depth. For robustness (and if wave induced turbulence is not important) Delft3D-FLOW produces this message and continues with Deltas=water depth.

Some suggestions on the possible cause:
- The WAVE data on which the computation of Deltas is based might be too old compared to the FLOW situation. In this case you should do a WAVE calculation more often.
- The WAVE grid might be too coarse compared to the FLOW grid and thus miss a shallow water region. In this case you should use a more detailed WAVE grid

I'll ask a colleague-specialist whether he has more suggestions.

Regards,

Adri
RM
Ruairi MacIver, modified 5 Years ago.

RE: Delft3D-FLOW: *** ERROR Deltas > water depth in TRATUR

Padawan Posts: 45 Join Date: 5/1/13 Recent Posts
Hi Adri,

Thanks for comprehensive explanation and suggestions.

Regarding the suggestions, here is a little more information that might help your specialist colleague.
1) The model couples FLOW and WAVE using the 'Online Delft3D-WAVE' option and the FLOW model has the interval between writing com files set to 60 minutes at present. So the WAVE model is executed every 60 minutes. The WAVE model is non-stationary with the coupling interval set to 60 minutes (set automatically as a consequence of the coupling with the FLOW model) and a time step of 60 minutes. The logic for the time step is the time (and spatially) varying boundary conditions for the wave model are provided at an interval of 3 hours.
2) The simulation in which the Deltas error was reported used a WAVE grid with a length scale of ~1500m while the FLOW grid had a length scale of ~150m (for the 3D domain). This simulation was an initial run and I intend to re-run the simulation where the WAVE model incorporates a nested domain with a length scale of ~500m. I guess whether this improves the situation will depend on how quickly the bathymetry varies in the region.

Would appreciate learning of the opinion of your colleague-specialist.

Regards
Ruairi
Adri Mourits, modified 5 Years ago.

RE: Delft3D-FLOW: *** ERROR Deltas > water depth in TRATUR

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

Can you attach your model input to a post here at this forum? Ideally simplified and still showing the problem. Mailing me is an alternative.

Thanks.

Adri
RM
Ruairi MacIver, modified 5 Years ago.

RE: Delft3D-FLOW: *** ERROR Deltas > water depth in TRATUR

Padawan Posts: 45 Join Date: 5/1/13 Recent Posts
Hi Adri,
I'll have a look at simplifying the model and get back to you.
Apologies for the delay in responding but I'm sure you have been busy regardless.
Regards
Ruairi