5.
SUMMARY AND FUTURE WORK
In this paper, we have presented a new unstructured grid morphodynamic model which
makes use of the existing ADCIRC finite element hydrodynamic model and a new DG finite
element sediment transport/morphological model.
Specific details were given on the
implementation of the DG method, and the model was shown to produce good results in three
idealized test cases. In the first test case it was verified, through the use of the Exner model, that
the method achieves second-order convergence in space. Additionally, it was demonstrated how
the DG method can accurately capture steep gradients in the bathymetry without the introduction
of spurious spatial oscillations. The second and third test cases demonstrated how the full
morphodynamic modelling system can be used to predict medium-term morphological changes of
the bed in channels and tidally dominated coastal inlets.
We conclude with some comments on the current development of this morphodynamic
modelling system, in terms of both physical and numerical features that will be implemented. In
this paper, we have only considered sediment transport due to currents. However, in many
coastal scenarios short waves, which interact with the current through the introduction of
radiation stress terms in the momentum equations, can be the dominant force in the sediment
transport process. Therefore, future work will involve coupling a wave model component into the
modelling system to include the effects of waves in both the hydrodynamics and sediment
transport processes. Numerically, as was previously indicated, the present model is only one
component of a suite of DG models that are currently being developed. Other DG model
components will include a 2DDI DG hydrodynamic model (see Kubatko, et al., 2005) and 2DDI
DG transport models for salinity and temperature. In many applications, these models will be
used in advection dominated flow scenarios such as coastal inlets. The DG method is particularly
advantageous for these types of situations.
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