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

 


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RE: Thatcher-Harleman boundary conditions

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Thatcher-Harleman boundary conditions
baroclinic thatcher halerman
Answer (Unmark)
2/22/17 8:38 PM
Hi all,

I would like to know how to set up Thatcher-Harleman boundary conditions in a 3D baroclinic sigma and Z layer case. My outflow boundary velocity field is fine, however I'm facing trouble in my inflow boundary with higher than expected velocity. I think that Thatcher-Harleman might help, yet I haven't found a conclusive information about which values to use. Any tips will be very helpful.

Thanks a lot in advance

Fernando Tulio Camilo Barreto
RE: Thatcher-Harleman boundary conditions
Answer (Unmark)
3/17/17 4:13 PMas a reply to Fernando Barreto.
Hi Fernando,

Thatcher-Harleman boundary conditions are used to avoid the discontinuity in the concentration at the turn of the flow between the imposed value and the computed value. It used only for transport, but not for velocity itself, I believe. Refer to Delft3D-FLOW manual Section 9.4.2.2.

Hope this is helpful,

Qinghua
RE: Thatcher-Harleman boundary conditions
Answer (Unmark)
5/25/17 2:45 PMas a reply to Qinghua Ye.
Hej,
hope I can join the discussion and get some information about the Thatcher-Harleman BC.

I am implementing the sediment process to my model and don´t know or do not have the experiences to use the right value for the Thatcher-Harleman time lag.

I computed some tests with 10, 60, 90 and 120 min and haven´t detected any huge differences.What is your experience and advice?

Thanks a lot,
cheers
Manuela
RE: Thatcher-Harleman boundary conditions
Answer (Unmark)
6/30/17 10:24 PMas a reply to Manuela König.
Manuela,

Very good question. I would expect Thatcher-Harleman BC won't have strong effect , for example, if the concentration difference is not so big and also if the transit time is resolved by the time steps. etc..

So it depends on the physical system you are modeling.

Greetings,

Qinghua