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

 

 

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Wave boundary condition - point source

SM
Samantha Maticka, modified 1 Month ago.

Wave boundary condition - point source

Youngling Posts: 6 Join Date: 10/2/20 Recent Posts
Hello,

I am trying to run Delft3D with just waves. I am using a curvilinear grid and would like to force it with time-varying waves that approach from the southwest. Can anyone advise on the best wave to do this? What I have tried is resulting in a point-source effect of waves rather than a spatially uniform forcing. I included pictures below.

I have field observations from a single location that I would like to force my model with. It is about 20km from my area of interest. Currently, I am using a curvilinear circular domain, and I am applying a non-stationary time-varying boundary forcing by using a TPAR file, specifying a 'segment' type of boundary in the [Boundary] block of the .mdw file, and declaring specific times to perform the calculations as [TimePoint] blocks. Something like this:

[TimePoint]
   Time                 =  0.000000000000000000e+000             
   WaterLevel           =  1.000000000000000000e+000         
   XVeloc               =  0.000000000000000000e+000         
   YVeloc               =  0.000000000000000000e+000         
   WindSpeed            =  0.000000000000000000e+000         
   WindDir              =  0.000000000000000000e+000  
[TimePoint]
   Time                 =  60.0      
   WaterLevel           =  1.000000000000000000e+000         
   XVeloc               =  0.000000000000000000e+000         
   YVeloc               =  0.000000000000000000e+000         
   WindSpeed            =  0.000000000000000000e+000         
   WindDir              =  0.000000000000000000e+000  
...
...[Boundary]
   Name                 = PointP6                  
   Definition           = xy-coordinates
   StartCoordX          = 575571.0
   EndCoordX            = 575571.0
   StartCoordY          = 8177208.0
   EndCoordY            = 8177208.0 
   SpectrumSpec         = from file        
   Spectrum             = spectral.bnd


I tried using a 15-point segment for the boundary (~1/15th of the perimeter), but the accuracy reported in the PRINT file from SWAN suggested that the model did not converge. So I reduced it from 15 points along the encompassing boundary to 2 points. It looked to converge, but both results had somewhat of a 'beam-like' behavior.

Any suggestions would be greatly appreciated!!

Thank you emoticon
Sam
This is what our results look like. For a depth like this (outside the red circle is not part of the domain):
The significant wave height looks like this (1st is 15-point boundary, 2nd is 2-pt):

and 

but this is what we would like them to look like: