An experimental study of the hydrodynamic impact of turbine layout and design considerations in tidal range schemes

Leech, Catherine 2022. An experimental study of the hydrodynamic impact of turbine layout and design considerations in tidal range schemes. PhD Thesis, Cardiff University. Item availability restricted.

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Abstract

Tidal Range Energy (TRE) is a reliable and sustainable source of energy found in abundance along the UK coast. It is thus far undeveloped on our shores due to environmental and financial concerns which have hindered it from competing with offshore wind and other renewable sources to meet UK energy demand. With current challenges to find clean and secure energy sources it is worth addressing these environmental concerns in order for TRE to reach its potential in our waters and worldwide. The present study looks specifically at the hydrodynamic impacts of the turbines in Tidal Range Schemes (TRSs) and how these are affected by different design parameters, including: the number of turbines, turbine spacing, TRS shape and TRS bed conditions. Physical experiments were conducted in the Hydro-environmental Research Centre at Cardiff University to quantify the changes in velocity induced by these design adaptations. Interruption to study reduced the number of physical experiments able to be carried out and numerical modelling was investigated to supplement results. Underlying asymmetrical flow in the laboratory impacted experimental results and presented challenges for calibrating the numerical model. Results from the physical experiments revealed that velocity patterns are most influenced by turbine spacing and that tightly spaced turbines lead to the greatest impact on baseline conditions due to concentrated wake effects. Wider spacing promotes slower circulation which would enable other activities to take place within TRSs but may lead to issues with water quality if flows are too slow to facilitate effective flushing. Both square and rectangular TRS designs showed similar results with regards to turbine spacing and circulation inside the TRS, but the rectangular TRS led to greater blockage effects outside the TRS. This emphasises the need for site specific design to take coastal conditions into account. Neither bed material nor bed slope were found to cause a significant difference to baseline flow conditions. Overall, turbine spacing had a greater impact on flow conditions than the number of turbines, and central placement with wider spacing was found to be best for maintaining natural conditions.

Item Type:	Thesis (PhD)
Date Type:	Completion
Status:	Unpublished
Schools:	Engineering
Uncontrolled Keywords:	1) Tidal Range Energy 2) Tidal Range Structure 3) Tidal Lagoon 4) Turbine Spacing 5) Physical Modelling 6) Hydrodynamic Impact Assessment
Date of First Compliant Deposit:	19 May 2023
Last Modified:	06 Jan 2024 02:05
URI:	https://orca.cardiff.ac.uk/id/eprint/159717

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