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

Initial conditions

Fernando Barreto, modified 7 Years ago.

Initial conditions

Padawan Posts: 74 Join Date: 6/21/12 Recent Posts
Hi everyone. I know that space varying inital conditons can be made using QUICKIN. But i would like to sclarify two points:

1) For the case of simulating a 3D example, considering 5 layers, how can I specify the initical conditions for all the layers?


2) the another point is if I can enter values of any property (velocity for instance) over the domain along the simulation. Enter fields of velocity with a time step of 1 hour, for instance. That is, entering velocity values ??along the domain hour.


Thanks
Emiel Moerman, modified 7 Years ago.

RE: Initial conditions (Answer)

Padawan Posts: 84 Join Date: 3/10/11 Recent Posts
Hi Fernando,

With respect to your first question, have a look at Section A.3.9 of the Delft3D-FLOW manual. The order of the *.ini file is:

1) water level
2) u-velocity (for each (k)-layer)
3) v-velocity (for each (k)-layer)
4) salinity (for each (k)-layer, if selected)
5) temperature (for each (k)-layer)
6) constituent 1(for each (k)-layer)
7) constituent 2 (for each (k)-layer)
8) constituent n (for each (k)-layer)

Regards,

Emiel
Fernando Barreto, modified 7 Years ago.

RE: Initial conditions

Padawan Posts: 74 Join Date: 6/21/12 Recent Posts
Hi Emiel, do you have some example file of a initial file for N layers?

Thanks!
Fernando Barreto, modified 7 Years ago.

RE: Initial conditions

Padawan Posts: 74 Join Date: 6/21/12 Recent Posts
For example:

Mmax = 25 and Nmax = 33

{33 records with 25 values each} {Water elevation}

The number of lines is controlled by the Nmax (number of grid points in N (V or ) direction). I thought that was controlled by Mmax = 25.
Emiel Moerman, modified 7 Years ago.

RE: Initial conditions (Answer)

Padawan Posts: 84 Join Date: 3/10/11 Recent Posts
Hi Fernando,

I attached an example file. I set-up a simple grid, 2x3 grid cells using RGF-GRID. For the example I assumed 4 layers over the vertical.
Subsequently, using QUICKIN (saving as depth-files), I made all of the ini-files of the different parameters separately, consisting of:

water level (value = 1m)
u-velocity layer 1 (value = 0.1)
u-velocity layer 2 (value = 0.2)
u-velocity layer 3 (value = 0.3)
u-velocity layer 4 (value = 0.4)
v-velocity layer 1 (value = 0.5)
v-velocity layer 2 (value = 0.6)
v-velocity layer 3 (value = 0.7)
v-velocity layer 4 (value = 0.8)
salinity layer 1 (value = 31)
salinity layer 2 (value = 32)
salinity layer 3 (value = 33)
salinity layer 4 (value = 34)
temperature layer 1 (value = 21)
temperature layer 2 (value = 22)
temperature layer 3 (value = 23)
temperature layer 4 (value = 24)

Using a text editor, I combined all of the individual parameter (in the order given above) into the attched file (example.ini).
Attached is also the example grid and some example depth file for a few initial conditions parameters (u-velocity, layer 1 and salinity, layer 3).

Note that for a 2x3 grid you get a depth file of 3x4 values + a row and columns of -999 values, (so size = 4x5).

Hope it helps, it should be easy: just make the individual parameters files using quickin and paste them together in the correct order using a text editior.

Regards,

Emiel
MR
mohammad rahmanian, modified 7 Years ago.

RE: Initial conditions

Youngling Posts: 6 Join Date: 5/27/12 Recent Posts
Hi Dear.Emiel

Your description was very great. I deleted my post as soon as I found your meaning.
My project has only Salinity process so it have Water level and Salinity initial conditions.
As you said , I first defined water level values for each layers and next I defined salinity values for each layers into the <ini> file but when I try to run the model it does not work and this Error "ERROR Premature EOF in file initial-condition.ini" appears.
My question is , Delft3D is defined to just simulate salinity without v or u velocity or something like that ?

I attached related files and you can check those.

Best regards

Mohamad
Emiel Moerman, modified 7 Years ago.

RE: Initial conditions

Padawan Posts: 84 Join Date: 3/10/11 Recent Posts
Hi Mohammad,

In the *.ini file, you need to define at least the parameters: water level, u-velocity, v-velocity and then dependent on your selection (salinity and or temperature) those parameters as well. So you should define the u- and v-velocity as 0 in the * ini file in your case:

- water level (spacially varying field, defined in Quickin or from previous simulation)
- u-velocity (uniform value over the grid of 0)
- v-velocity (unform value over the grid of 0)
- salinity (spacially varying field, defined in Quickin or from previous simulation)

Regards,

Emiel
MR
mohammad rahmanian, modified 7 Years ago.

RE: Initial conditions

Youngling Posts: 6 Join Date: 5/27/12 Recent Posts
Hi Dear.Emiel

Special thank you , your description was perfect.

Best regards

Mohamad
AM
Abdulla Mohamed, modified 6 Years ago.

RE: Initial conditions

Youngling Posts: 16 Join Date: 6/12/13 Recent Posts
Hello,

This thread has been very helpful to a beginner like myself. I am hoping someone might have some hints for me to move forward with a model I am trying to implement. Any advice would be much appreciated.

I am trying to set up a delft3D model to look at flow conditions and I am trying to implement the following as boundary conditions for the model:
1. Time series water levels ( I have a water level time series at 15 min intervals at the boundary for the entire three months I am trying to model )
2. Time series, depth varying salinity file with 10 sigma layers ( salinity for each sigma layer at 15 min intervals for the entire three months I am trying to model )

I am wondering what would be the best way to implement these boundary conditions so that the model will use the time series water level boundary and the time series depth varying salinity data as boundary conditions.

Few things I am trying to clarify are:

(a) Should these be defined as boundary conditions ( .bct ) file or should they be defined as initial conditions ( .ini ) file?

(b) I think I figured out how to make the ( .bct ) for the water level time series. Can I incorporate the depth varying salinity time series in the same .bct file that I use for the water level time series?

Any advice would be much appreciated.

Cheers,
Abdulla.
Adri Mourits, modified 6 Years ago.

RE: Initial conditions (Answer)

Yoda Posts: 1221 Join Date: 1/3/11 Recent Posts
Hi Abdulla,

Yes this should be specified in a .bct file. The Delft3D-GUI will help you with creating it.

With respect to the initial conditions, you have the following options:
  • A "cold start": just specify a constant initial water level and let the model run some time (spin-up time) before "using" the results.
  • A "hot start": First do the step above and restart using the generated map-file
  • Something inbetween: Generate a detailed initial condition manually. This is a lot of work and will be difficult to optimize.


Regards,

Adri
Julio Werner Yoshioka Bernardo, modified 7 Years ago.

RE: Initial conditions (Answer)

Youngling Posts: 9 Join Date: 4/10/11 Recent Posts
Fernando,

What I am trying now, regarding your second question,
is just edit restart files using trirst MATLAB function (see delft3d MATLAB interface documentation).
I did not find any an easier way to automate that.
In my case I'm doing series of tracers experiments and I have to put instantaneous sources of tracer after the model achieve the steady state.

Best Regards,
Fernando Barreto, modified 7 Years ago.

RE: Initial conditions

Padawan Posts: 74 Join Date: 6/21/12 Recent Posts
Thanks for the answers, I will study all your the information.

Thanks