Effect of array on turbines:
The few factors that the design of an efficient tidal array relies on are the adopted spacing between
the turbines and their mutual interplay, as well as their capacity. (Stallard, T., et al, 2013) (Tidal
Energy Resource Assessment for Tidal Stream Generators, 2007)
The power per turbine, arrangement and density of the turbine effects the performance and
economics of a turbine in a tidal array. (Vennel, Ross, 2011)
The turbine arrangement also has an effect on the optimal global blockage at which the power of
the turbine attains its maximum value. As the rate of increase of the power per turbine from an
array spanning the whole channel width to the optimal partial array diminishes with increasing
blockage, the optimal global blockage will also decrease. (Gong, Xianliang, et al, 2018)
The experimental testing of arrays of tidal turbines could not be carried out to the fullest due to the
lack of facilities that allow to place multiple devices and control flow conditions. (ScienceDirect,
2014)
Turbines that are deployed in several rows in a staggered manner is accepted to be more efficient
than those that are deployed in a central layout. (ScienceDirect, 2019)
In a tidal farm, turbulence intensity and the turbulence length, most importantly, scales of the freestream flow that directly influences the wake recovery after the first rows. (Mycek, Paul, et al,
2013) (Ouro, Pablo, et al, 2017)
Both single row and multiple-row array configurations were developed in order to obtain an optimal
turbine array in the specified area, with the different turbine spacing being measured tip-to-tip.
The multiple-row array is arranged in a staggered manner. The tidal flow field that is in the region
inside the turbans is disturbed by many devices and hence it is difficult to obtain a velocity that is
appropriate upstream of the turbines. Extractable power of the turbines increases as the number of
turbines increases. (Chen, Yaling, et al, 2015) (Jacobson, 2012)
The performances of single row turbines are generally better than that of multiple-rows.
For single row array, the laterally close configuration improves the performance of individual
turbine, hence more power can be extracted by turbines located closer to the shallow areas.
As for multiple-row array, the performance of inside turbine is significantly influenced by the
upstream wakes when the turbine density is high, as explained previously. (Muljadi, E, 2003)
(ScienceDirect, 2015)
While the flow is accelerated on two sides of turbine array, and the local flow is more enhanced
close to shallow areas. However, little sign of bypass flow is observed around tidal array with
relatively lower turbine density, which is advantageous to the power extraction. (Vogel,
Christopher, 2019)
The changes in the flow field were analysed to examine the disturbance caused by turbine arrays on
the local hydrodynamics. It was found that the tidal flow was significantly reduced in force in the
swept area and downstream. It was observed that the flow was accelerated on either side of the
turbine array and that the local flow was enhanced closer to the island. However, a little sign of
bypass, which is advantageous to the power extraction with a relatively low turbine density was also
observed. (Draper, S., et al, 2013)
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linkinghub.elsevier.com/retrieve/pii/S0889974619301161.
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Energy Extraction near an Island.” Computers & Geosciences, vol. 77, 2015, pp. 20–28.
Crossref, doi:10.1016/j.cageo.2015.01.008.
3. Draper, S., et al. “Energy Potential of a Tidal Fence Deployed near a Coastal Headland.”
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an Island.” ScienceDirect, 1 Apr. 2015,
linkinghub.elsevier.com/retrieve/pii/S0098300415000096.
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410–17. Crossref, doi:10.1115/1.1621674.
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Prototype.” Journal of Fluids and Structures, vol. 71, 2017, pp. 78–95. Crossref,
doi:10.1016/j.jfluidstructs.2017.03.009.
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Configurations.” Journal of Marine Science and Application, 15 Mar. 2019,
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