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. 




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



Message Boards

incoming flow : zero concentration gradient of incoming flow.

hani ramadhan, modified 2 Years ago.

incoming flow : zero concentration gradient of incoming flow.

Youngling Posts: 6 Join Date: 3/31/13 Recent Posts

Dear all,

Is that possible to define zero gradient of concentration at open boundary so that the concentration of active substances will have the same number with ambient concentration? I need this because I don't have data about incoming flow concentration for some active substances. I really need advice about this.

Thanks and best regards

Hani Ramadhan

Arjen Markus, modified 2 Years ago.

RE: incoming flow : zero concentration gradient of incoming flow.

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

Unfortunately, no, that is not possible (a limitation of the implementation, not of the mathematics, although I can see some peculiarities in that respect ...). There are two ways I can see you can solve this:

* Do a calculation with the boundary concentrations set to zero and see what "overall" concentrations develop for these substances (that will work only if you have processes that form them or waste loads that introduced them, of course. Otherwise the concentrations will remain zero).

* Use the characteristics of these substances and measurements from similar water bodies to estimate the concentrations on the boundaries.


Note: even if a zero-gradient boundary condition would have been possible, it would only have worked if the conditions for the first solution are fulfilled.