Tidal Model
Description
The tidal model used within this project simulates a hypothetical site where the water velocity varies between 0 and 5 m/s over a tidal cycle. This is representative of the velocity range that a tidal current turbine is likely to experience in some of the high performing sites within the UK. The model was developed in an Excel spreadsheet and uses a double sinusoid approximation for a tidal cycle; one with a period of 12.4 hours representing the diurnal tidal ebb and flow cycle and one with a period of 353 hours representing the fortnightly spring neap period. The velocity profile over this tidal cycle can be represented by the following equation:
Where Ko and K1 are constants determined from the mean spring peak and the ratio between the mean spring peak and the mean neap currents, T1 is the spring neap period and To is the diurnal tidal period.
Not included in the model are the potential effects on the tidal current velocity, resulting from external factors such as residual momentum, wind fetch and density variations, passing waves and global oceanic marine circulation. For a more detailed approximation these could be factored in some way; however, when a strong tide is thought to be flowing at the sites being identified as suitable locations for power generation, the effect of these external factors is thought to be negligible.
