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Title: Development of a fully coupled, unstructured grid, coastal morphodynamic model system
Author: Zheng, P.
Awarding Body: University of Liverpool
Current Institution: University of Liverpool
Date of Award: 2017
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A new fully coupled, unstructured grid, three-dimensional coastal morphodynamic model system is developed in this research. Based on two original independent models, i.e. the original unstructured-grid version of the third generation spectral wave model Simulating WAves Nearshore (UnSWAN) and the original Finite Volume Coastal Ocean Model (FVCOM), the development of this model system is achieved by accomplishing the following procedures: Coupling UnSWAN with FVCOM to enable the full representation of the wave-current interaction in the nearshore region, by building a new wave-current coupling scheme based on the vortex-force (VF) approach to represent the wave-current interaction and developing a new coupling module to facilitate the communication between UnSWAN and FVCOM in the parallel computing and realise the model coupling procedure. A GLS turbulence model is also modified to better reproduce wave-breaking generated turbulence, together with a roller transport model to account for the effects of surface wave roller. An alternative wave model based on Mellor et al. is also implemented in the present model system. The original advection-diffusion (AD) module is modified for the representation of particle suspension and subsequent transport under the combined flows. In this module, the contribution of wave-induced stokes drift to particle transport is included which is absent in the original FVCOM model. A new bed load transport module based on the SANTOSS formulae is built to represent various processes within the oscillatory boundary layer. Based on the semi-unsteady "half-cycle" concept, this SANTOSS formulae distinguish the sediment transports during the positive “crest” and the negative “trough” half-cycles and have the advantages over the traditional steady ’equilibrium’ transport formula that many wave-induced unsteadiness effects are included, including the wave asymmetry, sediment grain size effects and etc. Finally, the wave, circulation, suspended sediment and bed-load transport modules are integrated into the fully coupled, three-dimensional coastal morphodynamic model system, in which a sediment continuity (Exner) equation is also included to resolve the morphology evolution.
Supervisor: Li, Ming ; Wolf, Judith ; Burrows, Richard ; Thorne, Peter Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral