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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Dependence on Spatially Varying Chezy Coefficient in Van Rijn 2000 eqs?

AO
Alejandra Ortiz, modified 1 Month ago.

Dependence on Spatially Varying Chezy Coefficient in Van Rijn 2000 eqs?

Youngling Posts: 4 Join Date: 2/26/13 Recent Posts

Ok if I use a spatially varying bed roughness (Chezy) file (.rgh) for a simple wave + flow model using the default sediment transport equations (IFORM = -1, van Rijn 1993), how exactly is the Chezy coefficient changing the bed roughness and subsequent sediment transport? I've been looking the flow manual and reading the underlying code and am a bit confused.

The scripts being called (I think) are listed below"

Start of model

1. Trisim --> tricom_init --> readmd --> rdhyb --> hybfil which reads in the spatially varying rgh file into cfurou & cfvrou

2. Trisol --> taubot which computes the bottom stresses accounting for roughness in cfurou & cfvrou, saves these into taub**

3. Trisol --> erosed, which calcs a critical shear stress (taucr) based on shield's D* --> eqtran --> tram1 --> bedbc1993, calseddf1993, and bedtr1993 together which calc. sed. transport according to van Rijn Formula 1993

How is the bed shear stress calc. by taubot used in step 3? I'm having trouble tracking these variables in the fortran code. I've used doxygen + graphviz but for some reason it doesn't show eqtran or any of the sediment transport eqs in the graphical analyses (it said it skipped some files when I ran it...no clue why).

 

I'm using one size non-cohesive sand (.3 mm d50) with constant offshore waves running for 36 hours. Thanks for helping out!

 

Aleja

sediment transport bed roughness