intro story Coast / Estuary

Coast / Estuary

Coastal systems are among the most dynamic physical systems on earth and are subject to a large variety of forces. The morphodynamic changes occurring to coastlines worldwide are of great interest and importance. These changes occur as a result of the erosion of sediments, its subsequent transport as bed load or suspended load, and eventual deposition. 
 
Estuaries are partly enclosed water bodies that have an open connection to the coast. Estuaries generally have one or more branching channels, intertidal mudflats and/or salt marshes. Intertidal areas are of high ecological importance and trap sediments (sands, silts, clays and organic matter).
Within the Delft3D modelling package a large variation of coastal and estuarine physical and chemical processes can be simulated. These include waves, tidal propagation, wind- or wave-induced water level setup, flow induced by salinity or temperature gradients, sand and mud transport, water quality and changing bathymetry (morphology). Delft3D can also be used operationally e.g. storm, surge and algal bloom forecasting. 
 
On this discussion page you can post questions, research discussions or just share your experience about modelling coastal and/or estuarine systems with Delft3D FM. 
 

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

 

 

Message Boards

GMRES Error

ZC
Zachary Cobell, modified 5 Years ago.

GMRES Error

Youngling Posts: 10 Join Date: 5/3/12 Recent Posts
Hi all:

I'm currently getting acquainted with debugging DELWAQ runs and I'm trying to understand where I should be looking for the error I'm seeing below:

Parallel processing with 1 processor(s)

SIMULATION STARTED

INTEGRATION ROUTINE = 16
TIME = 5D 0H 0M 0S . 0.00% Completed
ERROR in GMRES 1
Stopped with error code : 1
STOP 1


Any and all help is appreciated.

Thanks,

Zach
AM
Arjen Markus, modified 5 Years ago.

RE: GMRES Error

Jedi Knight Posts: 223 Join Date: 1/26/11 Recent Posts
One possible cause is that the timestep is too large. Integration option 16 uses fairly tight criteria for convergence by default and if the timestep is too large, convergence may not be reached within the given number of iterations. Unfortunately, it may be caused by segments with a very small volume (relative to the flow rate and the timestep).

The first thing to do is rerun with a smaller timestep.
ZC
Zachary Cobell, modified 5 Years ago.

RE: GMRES Error

Youngling Posts: 10 Join Date: 5/3/12 Recent Posts
Thanks Arjen. Can WAQ use a smaller time step than the output interval from Flow? If so, my problem seems easily solved.

Thanks
AM
Arjen Markus, modified 5 Years ago.

RE: GMRES Error (Answer)

Jedi Knight Posts: 223 Join Date: 1/26/11 Recent Posts
Yes, WAQ can take smaller timesteps:If the hydrodynamic timestep is 1 h, WAQ can take timesteps of 1 h, 30 min, 10 min, etc. as long as the hydrodynamic timestep is a multiple of the WAQ timestep.(Which also means that the hydrodynamic timestep is the _maximum_)
GR
GERMAN RIVILLAS, modified 2 Years ago.

RE: GMRES Error

Youngling Posts: 2 Join Date: 1/25/12 Recent Posts
Hi Arjen:

I'm debugging DELWAQ runs and appear the same error of Zachary. I'm trying to reduce the output time step from 1h to 30 min but the error persist. Do you have any idea to solve this compilation process?

Parallel processing with 1 processor(s)

SIMULATION STARTED

INTEGRATION ROUTINE = 16
TIME = 0D 0H 0M 0S . 0.00% Completed
ERROR in GMRES 1
Stopped with error code : 1
STOP 1


I saw this warning report in the input verification

Messages presented including .lsp file:
Number of WARNINGS : 1


Thanks for your help

Best regards
GR
GERMAN RIVILLAS, modified 2 Years ago.

RE: GMRES Error

Youngling Posts: 2 Join Date: 1/25/12 Recent Posts
I solved the problem!!

Cheers
AM
Arjen Markus, modified 2 Years ago.

RE: GMRES Error

Jedi Knight Posts: 223 Join Date: 1/26/11 Recent Posts
Good to hear that - how did you do it?
YX
yu jia xin, modified 1 Year ago.

RE: GMRES Error

Youngling Posts: 5 Join Date: 12/1/18 Recent Posts

Hello, I want to ask you how you solve this error, error in GMRES, I suspect that there is a problem with the hyd file, but there is no error in my hydrodynamic calculation, and it is 0 warning 0 error when running waq1, so I would like to ask how this should be solved, thank you!

AM
Arjen Markus, modified 1 Year ago.

RE: GMRES Error

Jedi Knight Posts: 223 Join Date: 1/26/11 Recent Posts

There is no relationship between the numerical methods used in Delft3D-FLOW/D-FLOW-FM and the methods in DELWAQ (well, with the exception of integration methods 19 and 20, but they are only applicable on regular grids). Therefore you cannot conclude anything about the fact there were no errors in the hydrodynamic calculation.

Also DELWAQ1 merely processes the input file - it does not check that the hydrodynamic database is free of problems.

That said, there must be something in the hydrodynamic database that is causing this. You may want to experiment with the constant DRY_THRESH (which controls the minimum thickness of water for a grid cell/segment to be regarded as wet) or the constants that control the iteration in GMRES - MAXITER and TOLERANCE