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


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Group Velocity Calculation for Multiple Wave Components

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Group Velocity Calculation for Multiple Wave Components
wave waves the governing equations
Answer (Unmark)
4/12/18 8:34 PM
Hi All,

I am a beginning coastal modeler and I haven't been able to find a general equation for wave group velocity, when more than two components are involved.

It seems that all the equations for group velocity I could find fall into one of the two approaches:

1. By taking the derivative of wave frequency with respect to wave number: i.e., del(omega)/del(k)

2. By multiplying the phase velocity C by a ratio n.

Both approaches, however, assume that the wave group consists of only two individual waves with very similar wave periods.

Is there any general equation available that can be used for any arbitrary number of waves with widely different periods?

Any help will be greatly appreciated. My apologies if this is such a basic question, but it has been bothering me to a great degree..