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

Model Validation

LH
Lumas Helaire, modified 7 Years ago.

Model Validation

Youngling Posts: 3 Join Date: 7/4/13 Recent Posts
Hello,
We are starting to test aa multi segment grid of the Lower Columbia River Basin. We are trying to validate a segment of our grid that runs from,the mouth of the Columbia River out to the Pacific Ocean. All forcing is defined in the sea segment of the grid. We have the North, South and Sea (Western) boundaries set as Water Level. The forcing for these boundaries are Astronomic set for A0 with 0 elevation and 0 phase. With these conditions water should not be moving. Below is a copy of the Flow output and error warnings we get when FLOW is run. Also, we are using Delft version 3.28.


*******************************************************************************
*** Start of trisim for Run: HCR_Ap1_sea ***
*** Simulation date: 2013-07-08 14:21:42 ***
*** ***
*** User: Portland State University 25741 ***
*******************************************************************************

*** MD FLOW file used: HCR_Ap1_sea.mdf

*** MESSAGE Double precision computation using reals of kind 8

*******************************************************************************
*** ***
*** Deltares, Delft3D-FLOW Version 3.61.00.12401, Aug 26 2010, 12:09:44 ***
*** ***
*******************************************************************************

*** Start of User Defined Model description
-
- Historic Columbia River
- Input files of the historic CR
- at the sea boundary
-
*** End of User Defined Model description

*** MESSAGE Local time zone is UTC - 8.0 hours
*** MESSAGE Using Unesco density formulation by default
*** MESSAGE Momentum solver cyclic method is specified
*** MESSAGE DRYFLP and DPSOPT both specified in MD-file. Using DPSOPT: MAX
*** WARNING File will not be created - Inconsistent comm. file times
*** MESSAGE Nodal factors updated at 2005-07-31 00:00:06.0000
*** MESSAGE Nodal factors updated at 2005-07-31 00:00:18.0000
*** MESSAGE Nodal factors updated at 2005-07-31 00:00:30.0000
*** MESSAGE Nodal factors updated at 2005-07-31 00:00:42.0000
*** MESSAGE Nodal factors updated at 2005-07-31 00:00:54.0000
*** MESSAGE Nodal factors updated at 2005-07-31 00:01:06.0000
*** MESSAGE Nodal factors updated at 2005-07-31 00:01:18.0000
*** MESSAGE Nodal factors updated at 2005-07-31 00:01:30.0000
*** MESSAGE Nodal factors updated at 2005-07-31 00:01:42.0000
*** ERROR Water level gradient too high > 25.00 m (per 0.5 DT) after 9 timesteps in the following points:
(m,n) = (61,0), s0, s1, abs(s0-s1): 0.884E+03 , 0.858E+03 , 0.265E+02
(m,n) = (62,0), s0, s1, abs(s0-s1): 0.884E+03 , 0.858E+03 , 0.265E+02
(m,n) = (63,0), s0, s1, abs(s0-s1): 0.884E+03 , 0.858E+03 , 0.265E+02
(m,n) = (64,0), s0, s1, abs(s0-s1): 0.884E+03 , 0.858E+03 , 0.265E+02
(m,n) = (65,0), s0, s1, abs(s0-s1): 0.884E+03 , 0.858E+03 , 0.265E+02
(m,n) = (66,0), s0, s1, abs(s0-s1): 0.884E+03 , 0.858E+03 , 0.265E+02
(m,n) = (67,0), s0, s1, abs(s0-s1): 0.884E+03 , 0.858E+03 , 0.265E+02
(m,n) = (68,0), s0, s1, abs(s0-s1): 0.884E+03 , 0.858E+03 , 0.265E+02
(m,n) = (69,0), s0, s1, abs(s0-s1): 0.884E+03 , 0.858E+03 , 0.265E+02
(m,n) = (70,0), s0, s1, abs(s0-s1): 0.884E+03 , 0.858E+03 , 0.265E+02
(m,n) = (71,0), s0, s1, abs(s0-s1): 0.884E+03 , 0.858E+03 , 0.265E+02
(m,n) = (72,0), s0, s1, abs(s0-s1): 0.884E+03 , 0.858E+03 , 0.265E+02
(m,n) = (73,0), s0, s1, abs(s0-s1): 0.884E+03 , 0.858E+03 , 0.265E+02
(m,n) = (74,0), s0, s1, abs(s0-s1): 0.884E+03 , 0.858E+03 , 0.265E+02
*** ERROR Flow exited abnormally
Fernando Barreto, modified 7 Years ago.

RE: Model Validation

Padawan Posts: 74 Join Date: 6/21/12 Recent Posts
try to put the alpha coefficiente equal to 1000 to decrease the reflections that occur at the begin of the simulation
Emiel Moerman, modified 7 Years ago.

RE: Model Validation

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

It might also be a timestep error. Have you tried reducing your timestep?

I know colleagues of mine at Deltares are still busy with modelling the Columbia River mouth in collaboration with USGS. During my MSc thesis I also modelled the mouth of the Columbia River with Delft3D. Have a look at:

http://repository.tudelft.nl/view/ir/uuid:0a39e67c-ec24-4264-b523-d3ece34f9da8/

So I am quite interested in your study. What is it that your are modelling specifically? Feel free to contact me personally at the email address below.

Kind regards,

Emiel Moerman

e-mail
LH
Lumas Helaire, modified 7 Years ago.

RE: Model Validation

Youngling Posts: 3 Join Date: 7/4/13 Recent Posts
Hello,

thanks to all those who responded to my query. I tried derefined the leading edge of the grid and added a reflection parameter. Those changes resolved the problem. I am now trying to apply realistic boundary conditions.

Lumas Helaire
Portland State University