New high and low resolution numerical models of the tidal currents through the Digby Neck passages
LE3 .A278 2013
Master of Science
Mathematics & Statistics
Nova Scotians require electricity to be generated from renewable sources, and tidal power can play a role in ful lling this desire. Understanding the energetic tidal currents in the Bay of Fundy is a necessary step in implementing tidal power systems. Numerical models are a vital tool to increase our understanding. This thesis describes a high-resolution numerical model of Grand Passage, Petit Passage, and Digby Gut, which will be used for the characterization of the turbulent ows found there. This thesis describes the development process used to create two grids for use in a numerical model. In the Finite Volume Coastal Ocean Model (FVCOM) the grids (one with a resolution of 15 meters and the other with a resolution of 125 meters) are combined with high resolution bathymetry and coastlines to create accurate models. Both 2D and 3D simulations are run for time periods of a few days to 40 days. The model results were validated against data collected from multiple Acoustic Doppler Current Pro ler (ADCP) deployments that were part of the South West Nova Scotia Tidal Energy Resource Assessment. The models do an excellent job of predicting tidal elevation and basic tidal ow. The 15 meter resolution model also predicts intra-tidal uctuations in the ow at the correct locations and times. However, the magnitude of the uctuations are generally too large, which can drastically increase the maximum speed modelled at a given location. In Digby Gut, where the bathymetry was of lower quality, the simulated tidal currents did not compare as well to the observed data. An analysis of the residual ows in Grand Passage was completed. The spatial structures seen in the numerical model are linked to the timeseries data. The same behavior is observed in the observations indicating coherent spatial structures exist in Grand Passage. The thesis illustrates that high-resolution numerical modeling can be used to pre- dict the ow in an energetic, dynamic ow environment. Further, it shows it is possible to use a high-resolution numerical model to glean insight about physical pro- cesses of tidal ows. Finally, the thesis concludes that increasing the accuracy of the modeled turbulence and uctuations remains an important next step.
The author grants permission to the University Librarian at Acadia University to reproduce, loan or distribute copies of my thesis in microform, paper or electronic formats on a non-profit basis. The author retains the copyright of the thesis.