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

Bottom roughness coefficient as a function of water depth

KA
Khalid Al-Asadi, modified 8 Years ago.

Bottom roughness coefficient as a function of water depth

Youngling Posts: 16 Join Date: 5/5/11 Recent Posts
Hello,

As I know in Delft3D until now, the bottom roughness coefficients (uniform or variable values) remain constant for the whole time steps. Is there any way can be used to incorporate a formula to calculate the bottom roughness coefficients at each time step? For instance. In my case study, the bootom roughness coefficient at any grid point varies at each time step and it is a function of water depth.

Thanks

Khalid
Adri Mourits, modified 8 Years ago.

RE: Bottom roughness coefficient as a function of water depth

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

Currently it is not possible to prescribe time varying bottom roughness.

What exactly do you want to model? May be you can use trachytopes, see section B.17 in the manual.

If you really want time varying bottom roughness: it's open source. Have a look at subroutine "https://svn.oss.deltares.nl/repos/delft3d/trunk/src/engines_gpl/flow2d3d/packages/kernel/src/compute/trtrou.f90".
You can add a call at the beginning of each half time step in subroutine "https://svn.oss.deltares.nl/repos/delft3d/trunk/src/engines_gpl/flow2d3d/packages/kernel/src/main/trisol.f90" to a new subroutine, where parameters cfurou and cfvrou get new values.

Hope this helps.

Regards,

Adri
KA
Khalid Al-Asadi, modified 8 Years ago.

RE: Bottom roughness coefficient as a function of water depth

Youngling Posts: 16 Join Date: 5/5/11 Recent Posts
Dear Adri,

Thank you for your help. I'm trying to simulate a marsh area with time varying bottom roughness. Could you please write again the subroutines' names because I think their names are not complete. For instance you wrote :

"https://svn.oss.deltares.nl/repos/delft3d/trunk/src/engines_gpl/flow2d3d/packages/kernel/src/compute
and
"https://svn.oss.deltares.nl/repos/delft3d/trunk/src/engines_gpl/flow2d3d/packages/kernel/src/main


, the above locations are folders contain many subroutines.


Khalid
Adri Mourits, modified 8 Years ago.

RE: Bottom roughness coefficient as a function of water depth

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

I think you have to zoom out in your internet browser. For some reason this "site-maintenance-tool" we're using does not wrap text when it does not fit in your window.

Anyway, the files I mentioned in my previous post are:
trtrou.f90 in directory compute and trisol.f90 in directory main.

Regards,

Adri
KA
Khalid Al-Asadi, modified 8 Years ago.

RE: Bottom roughness coefficient as a function of water depth

Youngling Posts: 16 Join Date: 5/5/11 Recent Posts
Hi Adri,
Thank you for your help. I'm trying to use the Tracytope. I read section B.17 in the manual, could you please help me to find more details about the calibration file and the area file ,specially the area fraction, and how can I write these files for huge domain?

Thanks

Khalid
Adri Mourits, modified 8 Years ago.

RE: Bottom roughness coefficient as a function of water depth

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

Attached is an example testcase. File "straight.df" contains one vegetation type. You can add as much types as you want in this file, one type per line. File "straight.aruv" contains one region (the full domain) refering to a type of vegetation. You can add as much regions as you want in this file (each referring to a vegetation type), one region per line.

By using regions, you can use this also for huge domains.

Regards,

Adri
BJ
Bo Jiang, modified 7 Years ago.

RE: Bottom roughness coefficient as a function of water depth

Youngling Posts: 1 Join Date: 4/17/12 Recent Posts
Dear Khalid,

I am currently also working on a project which requires to specify the time varying bottom roughness information. I just wonder have you successfully modified the code?

Rgds,
John Chiang
JL
João Lencart e Silva, modified 7 Years ago.

RE: Bottom roughness coefficient as a function of water depth

Padawan Posts: 70 Join Date: 3/30/11 Recent Posts
Dear Bo,

When you say your bottom roughness is a function of time can you tell me if this function is strictly dependent on water depth (free-surface elevation + depth at that point) or some other formulation?

João.
BJ
Bo Jiang, modified 7 Years ago.

RE: Bottom roughness coefficient as a function of water depth

Youngling Posts: 1 Join Date: 4/17/12 Recent Posts
hi Joao,

nope...i am trying to modified the bed roughness to be a function of sediment concentration which is a time series of input value. Therefore, the bed roughness should also be changing with time.
thanks!
JL
João Lencart e Silva, modified 7 Years ago.

RE: Bottom roughness coefficient as a function of water depth

Padawan Posts: 70 Join Date: 3/30/11 Recent Posts
Dear Khalid,

The Manning and Colebrooke-White bottom roughness parametrisations, unlike the Chezy are a function of water depth.
See discussion of the parametrisations in Soulsby (1998), Dynamics of Marine Sands, Volume: 249pp, Publisher: Thomas Telford.
Please see the D3D-flow manual for application of such parametrisations.

I used D3D and the Colebrooke-White in an article of Maputo Bay, Mozambique:
Lencart e Silva J.D., Simpson J.H., Hoguane A.M., Harcourt-Baldwin J-L. (2010) Buoyancy-stirring interactions in a subtropical embayment: A synthesis of measurements and model simulations in Maputo Bay. African Journal of Marine Science. 32, 1, 95-97.

Another example using the Manning (not with D3D) in the Ria Formosa, Portugal can be seen in:
J. M. Dias, M. C. Sousa, X. Bertin, A. B. Fortunato, A. Oliveira, (2009). Numerical modeling of the impact of the Ancão Inlet relocation (Ria Formosa, Portugal). Environmental Modelling and Software 24(6): 711-725