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

FLOW error

MV
mercy varghese, modified 7 Years ago.

FLOW error

Youngling Posts: 17 Join Date: 8/6/13 Recent Posts
I trying to simulate Surge cyclone Thane on the eastern cost of India using Delft 3D Flow. I have used Dash Board to create the inputs.
The rectangular grid is of 1.1km spacing with tim estep 0.25min (15sec).
The maximum courant number was around 9.
The grid spans over an area of 220kmX220km.
The advection scheme is kept as cyclic.
The wind drag coefficient changes at 30m/s.
The wind file is given in spider web format.

I always get an error water level exceeds 25m and the calculation is aborted.
What might be the reason. what should be done?

I tried changing the wind magnitudes at Cd changes, but the error still exists.
U
Arnold van Rooijen, modified 7 Years ago.

RE: FLOW error

Hi Mercy,

It seems like there is either something wrong in your boundary conditions or in your time step. However, I think your time step seems already relatively small... Perhaps you can check the modelled velocities in the last available time step?

Cheers,
Arnold
Qinghua Ye, modified 7 Years ago.

RE: FLOW error

Jedi Council Member Posts: 610 Join Date: 3/2/11 Recent Posts
Hi Mercy,

It seems like the model is not stable. I would say the model reacted reasonable, since a strong surface shear stress is imposed in the model. I don't have an universal approach for such a problem. But I would imagine if you have a meteo force not so sudden and impose it with a transit time, it might be not crash.

Furthermore, I would suggest you to join the Delft3D training course. There you might learn some tricks how to deal with this sort of problems. Refer to: http://www.deltaressystems.com/hydro/agenda/courses/training/318517/delft3d-basic-courses

Hope this would help a bit,

Qinghua