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

sediment problems

KW
Kidung Widhi, modified 7 Years ago.

sediment problems

Youngling Posts: 11 Join Date: 4/30/11 Recent Posts
hello all

i have a question about non-cohesive sediment modelling..
i try to set up a domain coastal model with time series current+water level bc in open sea and time series discharge bc input from river.. there are more than 5 rivers in my domain..
i run with 2 days simulation time, default sediment and morphological data except D50, bed thickness and scale factor..

i have problems with the result, the computation works fine until the end but there are some warnings..
its says WARNING Bed change exceeds 5.0 % of water depth after xxx time steps, location (m,n) = xxxx
and its just not one warning but many warnings..

firstly the result in open sea:
there aren't any movement except the edge of the open sea bc, the movement just step forward and backward in the same position not in the whole domain.. and after half days of simulation time the result just vanish until end of simulation..

secondly result in river:
i have at least 8 rivers in the domain, but the sediment result just at 2 rivers the others just blank no result at all.. the same with open sea result after half days of simulation the result just vanish like nothing at all..

it gives the same result whether i run in standalone or pararel with wave, and i already set up different scale factor but nothing change also..

anyone can give me some advice about sediment modelling ? maybe the setup in morphological or something else?
i appreciate it alot..

regards..
Arjen Luijendijk, modified 7 Years ago.

RE: sediment problems

Padawan Posts: 38 Join Date: 2/22/11 Recent Posts
Dear,
It is hard to judge without detailed information or pictures, but i suggest that you check your time step and make a simulation with the morphological scale factor at 1. You can check your time step with Quickplot: open the trim-file, then click 4th icon from left (says 'file dependent options'), there you see a button named 'check time step' - select trim file and you will see whether you meet all the criteria.

Regards, Arjen
Qinghua Ye, modified 7 Years ago.

RE: sediment problems

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

As Arjen mentioned, you should first check the Cr. number.

Can you also provide a bit more info? What kind of processes are activated in your model? Which version of the Delft3D-FLOW are you using? Are you using the VR2004 formula for a 2D modeling? Refer to http://oss.deltares.nl/web/delft3d/release-notes.

Regards,

Qinghua
KW
Kidung Widhi, modified 7 Years ago.

RE: sediment problems

Youngling Posts: 11 Join Date: 4/30/11 Recent Posts
hello all

thankyou for your answers..
I already checked the courant and attached in this reply, is there something wrong with the courant ?

I used Delft3D flow 4.00.02 and 2D modelling
regards..

Attachments:

Qinghua Ye, modified 7 Years ago.

RE: sediment problems

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

It seems to me the Cr number is ok in your case.

Are you using the VR2004 formula for a 2D modeling?

Regards,

Qinghua