Flood-ebb asymmetry of a tidal flow has important implications for net sediment transport and the potential extractable resource. The asymmetry of the tide in U.K. waters may be understood through the interaction of the M2 (principal lunar) and M4 (first even overtide of the M2) tidal constituents. The interaction of the M2 tide with a tidal-stream turbine will alter the M4 tide, both augmenting and reducing the M4 amplitude, leading to an alteration of flood-ebb asymmetry. In this chapter the impact of a row of tidal-stream turbines on the overtides of the M2 has been investigated through a numerical modelling study. Further, the way that additional turbines alter the way the turbines impact the shallow-water tides individually is explored. The results of the modelling show that when deployed in a row, on average, the peak velocity deficit and change to the current magnitude asymmetry (CMA) per turbine was less than were it deployed alone. The difference between the per turbine impact of turbines in a row and that of an individual turbine grew as the number of turbines in the row, and therefore the row blockage, increased. Additionally, the total area of the model domain experiencing a change to the M2 current and CMA > 1% increased with the addition of turbines to the row, for a row blockage >~10%, but remained similar to the single turbine case for lower blockage values. The implication of the change to the CMA by a turbine in a row for the asymmetry in energy conversion for its lateral neighbours was small as the turbines do not lie within the area of effect of their neighbours. However, the per turbine energy conversion increased as the number of turbines and row blockage increased, in line with theory.
- Tidal-Stream turbines
- Tidal asymmetry
- Tidal-Stream array
- Physical environment impact
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When simulating a real-world site, better representation of the harmonic generation within the model domain will be obtained by supplying the harmonic tides at the boundaries of the model (Le Provost and Fornerino 1985). As only an idealised case is considered in this work any choice of harmonics supplied at the boundaries would be somewhat arbitrary. Therefore, the simplest case was considered. The case of undistorted tides at either boundary, i.e. M2 tide with negligible harmonics.
Ahmadian, R., Falconer, R., & Bockelmann-Evans, B. (2012). Far-field modelling of the hydro-environmental impact of tidal stream turbines. Renewable Energy, 38, 107–116.
Baston, S., Waldman, S., & Side, J. (2014). Modelling energy extraction in tidal flows. In TerraWatt Position Papers (p. 102). MASTS.
Bruder, B., & Haas, K. (2014). Tidal distortion as pertains to hydrokinetic turbine selection and resource assessment. In Proceedings of the 2nd Marine Energy Technology Symposium, METS2014, 15–18 April, 2014, Seattle, WA.
Chen, L., & Lam, W. (2014). Slipstream between marine current turbine and seabed. Energy, 68, 801–810.
Churchfield, M., Li, Y., & Moriarty, P. (2011). A large-eddy simulation study of wake propagation and power production in an array of tidal-current turbines. In Proceedings of EWTEC 2011, Southampton.
De Dominicis, M., O’Hara-Murray, R., & Wolf, J. (2017). Multi-scale ocean response to a large tidal-stream turbine array. Renewable Energy, 114, 1160–1179.
DHI. (2016). MIKE 21 & MIKE 3 flow model FM, hydrodynamic and transport module, scientific documentation.
Dronkers, J. (1986). Tidal asymmetry and estuarine morphology. Netherlands Journal of Sea Research, 20, 119–131.
Garrett, C., & Cummins, P. (2007). The efficiency of a turbine in a tidal channel. Journal of Fluid Mechanics, 588, 243–251.
Kramer, S., Piggott, M., Hill, J., Kregting, L., Pritchard, D., & Elsaesser, B. (2014). The modelling of tidal turbine farms using multi-scale, unstructured mesh models. In Proceedings of the 2nd International Conference on Environmental Interactions of Marine Renewable Energy Technologies (EMIR 2014). Stornoway, Scotland.
Le Provost, C. (1991). Generation of overtides and compound tides (review). In B. Parker (Ed.), Tidal hydrodynamics. New York: Wiley.
Le Provost, C., & Fornerino, M. (1985). Tidal spectroscopy of the English Channel with a numerical model. Journal of Physical Oceanography, 15, 1009–1031.
Masters, I., Malki, R., Williams, A., & Croft, T. (2013). The influence of flow acceleration on tidal stream turbine wake dynamics: A numerical study using a coupled BEM-CFD model. Applied Mathematical Modelling, 37, 7905–7918.
Nash, S., O’Brien, N., Olbert, A., & Hartnett, M. (2014). Modelling the far field hydro-environmental impacts of tidal farms—A focus on tidal regime, inter-tidal zones and flushing. Computers & Geoscience, 71, 20–27.
Neill, S., Litt, E., Couch, S., & Davies, A. (2009). The impact of tidal stream turbines on large scale sediment dynamics. Renewable Energy, 34, 2803–2812.
Neill, S., Jordan, J., & Couch, S. (2012). Impact of tidal energy converter (TEC) arrays on the dynamics of headland sand banks. Renewable Energy, 37, 387–397.
Neill, S., Hashemi, M., & Lewis, M. (2014). The role of asymmetry in characterizing the tidal resource of Orkney. Renewable Energy, 68, 337–350.
O’Hara-Murray, R., & Gallego, A. (2017). A modelling study of the tidal stream resource of the Pentland Firth, Scotland. Renewable Energy, 102, 326–340.
Parker, B. (1991). The relative importance of the various nonlinear mechanisms in a wide range of tidal interactions (review). In B. Parker (Ed.), Tidal hydrodynamics. New York: Wiley.
Pawlowicz, R., Beardsley, B., & Lentz, S. (2002). Classical tidal harmonic analysis including error estimates in MATLAB using t_tide. Computers & Geoscience, 28, 929–937.
Potter, D. (2019). Alteration to the shallow-water tides and tidal asymmetry by tidal-stream turbines. Ph.D. thesis, Lancaster University.
Pingree, R., & Griffiths, D. (1979). Sand transport pathways around the British Isles resulting from the M2 and M4 tidal interactions. Journal of the Marine Biological Association of the United Kingdom, 59, 497–513.
Robins, P., Neill, S., & Lewis, M. (2014). Impact of tidal-stream arrays in relation to the natural variability of sedimentary processes. Renewable Energy, 72, 311–321.
Robins, P., Neill, S., Lewis, M., & Ward, S. (2015). Characterising the spatial and temporal variability of the tidal-stream energy resource over the northwest European shelf seas. Applied Energy, 147, 510–522.
Roc, T., Conley, D., & Greaves, D. (2013). Methodology for tidal turbine representation in ocean circulation model. Renewable Energy, 51, 448–464.
Roc, T., Greaves, D., Thyng, K., & Conley, D. (2014). Tidal turbine representation in an ocean circulation model: Towards realistic applications. Ocean Engineering, 78, 95–111.
Shields, M., Woolf, D., Grist, E., Kerr, S., Jackson, A., Harris, R., et al. (2011). Marine renewable energy: The ecological implications of altering the hydrodynamics of the marine environment. Ocean and Coastal Management, 54, 2–9.
Stallard, T., Collings, R., Feng, T., & Whelan, J. (2013). Interactions between tidal turbine wakes: Experimental study of a group of three-bladed rotors. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 371, 20120159.
Tritton, D. (1988). Physical fluid dynamics (2nd ed.). London: Clarendon Press.
Vennell, R. (2010). Tuning tidal turbines in a channel. Journal of Fluid Mechanics, 663, 253–267.
Vennell, R. (2012). Realizing the potential of tidal currents and the efficiency of turbine farms in a channel. Renewable Energy, 47, 95–102.
Vennell, R. (2013). Exceeding the Betz limit with tidal turbines. Renewable Energy, 55, 277–285.
Wang, Z., Jeuken, C., & de Vriend, H. (1999). Tidal asymmetry and residual sediment transport in estuaries. Technical Report Z2749, WL Delft Hydraulics, Delft, Netherlands.
This work was funded by a Natural Environment Research Council studentship, part of the ENVISON Doctoral Training Program, awarded to the lead author. Thanks also goes to DHI UK for providing a student licence for MIKE, allowing this work to be undertaken.
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Potter, D., Ilić, S., Folkard, A. (2020). Assessing the Impact of Rows of Tidal-Stream Turbines on the Overtides of the M2. In: Nguyen, K., Guillou, S., Gourbesville, P., Thiébot, J. (eds) Estuaries and Coastal Zones in Times of Global Change. Springer Water. Springer, Singapore. https://doi.org/10.1007/978-981-15-2081-5_13
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Print ISBN: 978-981-15-2080-8
Online ISBN: 978-981-15-2081-5