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

 


Message Boards

swan diag warning - length of segment short

KS
Kit Stokes, modified 2 Years ago.

swan diag warning - length of segment short

Youngling Posts: 9 Join Date: 11/8/16 Recent Posts
Hi all,

I'm getting a warning from a coupled wave-flow simulation in the swn-diag file for one of my four boundaries. The warning says:

"** Warning : Length of segment short, boundary values ignored".

I'm running condspecatdist using 2D spectra files as input at each location specified by condspecatdist. As you can see from an extract of the swn-diag file below, I'm not getting the warning at any of the other three boundaries. Oddly, the results seem to be ok, and I can see waves propagating in from all segments of all boundaries, so it would seem that it is not ignoring the boundary values, as the warning below indicates. But the warning is worrying, as I'm not sure why it is there, or what effect it is having in the model. Does anyone have any experience with this issue?

It looks like this:

BOUN SEGM IJ 0 240 153 240 &
VAR FILE 3.18 'North_2DSpec_1.bnd' 1 &
2.98 'North_2DSpec_2.bnd' 1 &
** Warning : Length of segment short, boundary values ignored
segment length= 2.13; [len]= 2.98
2.73 'North_2DSpec_3.bnd' 1 &
** Warning : Length of segment short, boundary values ignored
segment length= 2.13; [len]= 2.73
2.39 'North_2DSpec_4.bnd' 1 &
** Warning : Length of segment short, boundary values ignored
segment length= 2.13; [len]= 2.39
2.06 'North_2DSpec_5.bnd' 1 &
** Warning : Length of segment short, boundary values ignored
segment length= 2.13; [len]= 2.06
1.81 'North_2DSpec_6.bnd' 1
** Warning : Length of segment short, boundary values ignored
segment length= 2.13; [len]= 1.81

BOUN SHAPE JONSWAP 3.30 PEAK DSPR POWER

BOUN SEGM IJ 355 0 355 29 &
VAR FILE 0.00 'East_2DSpec_1.bnd' 1 &
0.19 'East_2DSpec_2.bnd' 1 &
0.26 'East_2DSpec_3.bnd' 1

BOUN SHAPE JONSWAP 3.30 PEAK DSPR POWER

BOUN SEGM IJ 4 0 355 0 &
VAR FILE 0.04 'South_2DSpec_1.bnd' 1 &
0.21 'South_2DSpec_2.bnd' 1 &
0.46 'South_2DSpec_3.bnd' 1 &
0.78 'South_2DSpec_4.bnd' 1 &
1.11 'South_2DSpec_5.bnd' 1 &
1.36 'South_2DSpec_6.bnd' 1 &
1.69 'South_2DSpec_7.bnd' 1 &
2.03 'South_2DSpec_8.bnd' 1 &
2.28 'South_2DSpec_9.bnd' 1 &
2.61 'South_2DSpec_10.bnd' 1 &
2.86 'South_2DSpec_11.bnd' 1 &
3.18 'South_2DSpec_12.bnd' 1

BOUN SHAPE JONSWAP 3.30 PEAK DSPR POWER

BOUN SEGM IJ 0 0 0 240 &
VAR FILE 2.15 'West_2DSpec_1.bnd' 1 &
2.02 'West_2DSpec_2.bnd' 1 &
1.69 'West_2DSpec_3.bnd' 1 &
1.36 'West_2DSpec_4.bnd' 1 &
1.10 'West_2DSpec_5.bnd' 1 &
0.78 'West_2DSpec_6.bnd' 1 &
0.45 'West_2DSpec_7.bnd' 1 &
0.20 'West_2DSpec_8.bnd' 1 &
0.00 'West_2DSpec_9.bnd' 1

$


Thanks in advance!
KS
Kit Stokes, modified 2 Years ago.

RE: swan diag warning - length of segment short

Youngling Posts: 9 Join Date: 11/8/16 Recent Posts
I eventually resolved this issue. I had mistakenly entered condspecatdist as the distance from the corner of the grid to each forcing location, rather than the distance from the start of the boundary segment to each forcing location. As the north boundary segment started half way along the side of the grid, this meant that the distances were actually off the edge of the grid, hence the warning. Now that I've resolved that issue, the warnings in the swan diag file have dissapeared.