Field measurement and numerical study of tidal current turbulence intensity in the Kobe Strait of the Goto Islands, Nagasaki Prefecture

Novo, Patxi Garcia; Kyozuka, Yusaku

doi:10.1007/s00773-016-0414-x

Cited by 14 publications

(8 citation statements)

References 26 publications

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“…As presented in Sect. 1, turbulence intensities between 0.1 and 0.2 at P1 in Tanoura Strait are similar to the results for Sound of Islay in Scotland (0.12-0.13) [11] or Kobe Strait in Japan (0.15-0.17) [13]. As for P2 in the Naru Strait, the notable difference between the two tide directions has been also found in other areas with strong impact of geomorphologic conditions on the flow [12].…”

Section: Discussionsupporting

confidence: 84%

“…As for P2 in the Naru Strait, the notable difference between the two tide directions has been also found in other areas with strong impact of geomorphologic conditions on the flow [12]. In terms of streamwise length scale, both P1 and P2 conditions are close to the measured in Kobe Strait, Goto Islands, for 2-m/s velocities in the ebb direction [13]. Values for flood tide in Kobe Strait (≈ 12 m), as well as for the point analysed by Milne et al [11] in the Sound of Islay (11-14 m), are significantly higher, but still comparable.…”

Section: Discussionsupporting

confidence: 73%

“…Under similar average velocity and time period conditions, extreme velocities close to 25% higher than the mean value were reported in the Sound of Islay [11]. In the Kobe Strait study [13], for a 5-min period with an averaged velocity of 2 m/s, instantaneous values close to 3 m/s were observed. These extreme velocities, which cannot be predicted by regional-scale numerical modelling [14], might lead to turbine damage, as happened in the Bay of Fundy in 2009.…”

Section: Introductionsupporting

confidence: 69%

“…Results presented in this study for one of the two measuring points show notably higher turbulence intensities (> 25%) in the ebb tide, which is likely to be related to the presence of a headland close to the measuring device installation point. Finally, in Kobe Strait (Japan) [13], ADCP data at 8 m from the bottom show similar streamwise turbulence intensity values for flood and ebb tide (0.17-0.15), whilst length scale is almost double for the flood direction (12.3-6.64 m). Thus, there seems to be a direct relation between the local geomorphologic conditions and the turbulence characteristics of a site.…”

Section: Introductionmentioning

confidence: 75%

“…Other authors have focused on characterising the turbulence conditions at the most promising areas for tidal current energy extraction to predict the behaviour of turbines at these locations. These field studies are based on the measurement of high-frequency velocity data [11][12][13]. The results obtained differ depending on the location.…”

Section: Introductionmentioning

confidence: 99%

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Analysis of turbulence and extreme current velocity values in a tidal channel

Novo¹,

Kyozuka

2018

J Mar Sci Technol

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Tidal stream energy has emerged as one of the most promising alternative energy sources to the use of fossil fuels. Nevertheless, there are some crucial issues that must be overcome. One of these key aspects is the response of tidal stream energy converters to the extreme velocities related to high-frequency velocity perturbations from the mean current speed. In this study, the dependence of this velocity fluctuation on the turbulence conditions of the flow is analysed based on the data measured during 1 week by two Acoustic Doppler velocimeters in two tidal channels in the Goto Islands, Japan. At one of the channels, where maximum 3-min averaged measured velocity is 1.7 m/s, extreme values over 3 m/s were observed. Turbulence intensity ranges between 10 and 35%, with a clear contrast between flood and ebb conditions at one of the measuring points. Peak velocity, in terms of a peak-to-averaged ratio, and turbulence intensity calculated for 3-min periods were compared, obtaining linear trends with similar slopes for both measuring points and under different flow conditions. Since turbulence conditions can be simulated by numerical modelling, the presented correlation opens the door to prediction of extreme velocities, reducing the need for in situ measurements.

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Section: Discussionsupporting

confidence: 84%

Section: Discussionsupporting

confidence: 73%

Section: Introductionsupporting

confidence: 69%

Section: Introductionmentioning

confidence: 75%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Analysis of turbulence and extreme current velocity values in a tidal channel

Novo¹,

Kyozuka

2018

J Mar Sci Technol

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Engineering analysis of turbulent flow measurements near Kuchinoshima Island

2018

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Ocean current measurements from near Kuchinoshima Island are analyzed to consider turbulence characteristics with regard to the engineering design of an ocean current turbine. The location of the measurements is offshore of Kuchinoshima in the Tokara Strait within the path of the Kuroshio Current. The measurement campaign was from January 15 to 16, 2016 using the Nortek Signature 500 ADCP and Nortek Vector ADV. Turbulence characteristics of turbulence intensity, integral timescale, and integral length scale are evaluated at 1 m increments above the seabed. Doppler noise removal is performed and power density spectrums are presented. The findings will lead to more accurate loading calculations and simulations for performance evaluation.

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