Quantifying turbulence for tidal power applications

Thomson, Jim; Polagye, Brian; Richmond, Marshall C.; Durgesh, Vibhav

doi:10.1109/oceans.2010.5664600

Cited by 44 publications

(46 citation statements)

References 12 publications

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“…The turbulence intensity can be calculated as a function of time; however, attention must be paid to time durations of slack current, in which the mean speed approaches zero [20]. Under this circumstance, the denominator goes to zero causing the turbulence intensity value to blow up.…”

Section: Turbulence Intensity Metricmentioning

confidence: 99%

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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Section: Turbulence Intensity Metricmentioning

confidence: 99%

Engineering analysis of turbulent flow measurements near Kuchinoshima Island

2018

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“…It is likely that the increased turbulent fluctuations directly behind the device act to aid the velocity recovery within this zone (up to 3D), and once they decrease the velocity recovery slows down in the region beyond 3D downstream. Due to the fact that flow was created artificially, by towing the device through the fluid, the ambient turbulence intensity in the lake was relatively low (< 2 %), in comparison to turbulence intensity values measured at a tidal site, which have been quoted in the range of 10 % and above (McCann et al, 2008;Thomson et al, 2010). Studies have shown that the recovery of velocity in the wake of a TEC is faster in flows with higher ambient turbulence intensity (MacLeod et al, 2002).…”

Section: Overview Of Wake Characteristicsmentioning

confidence: 80%

A large scale model experimental study of a tidal turbine in uniform steady flow

2015

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An experimental study measuring the performance and wake characteristics of a 1:10 th scale horizontal axis turbine in steady uniform flow conditions is presented in this paper.Large scale towing tests conducted in a lake were devised to model the performance of the tidal turbine and measure the wake produced. As a simplification of the marine environment, towing the turbine in a lake provides approximately steady, uniform inflow conditions. A 16m long x 6m wide catamaran was constructed for the test programme. This doubled as a towing rig and flow measurement platform, providing a fixed frame of reference for measurements in the wake of a horizontal axis tidal turbine. Velocity mapping was conducted using Acoustic Doppler Velocimeters.The results indicate varying the inflow speed yielded little difference in the efficiency of the turbine or the wake velocity deficit characteristics provided the same tip speed ratio is used. Increasing the inflow velocity from 0.9 m/s to 1.2 m/s influenced the turbulent wake characteristics more markedly. The results also demonstrate that the flow field in the wake of a horizontal axis tidal turbine is strongly affected by the turbine support structure.

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“…ADV measurements have been extensively used to quantify turbulence and understand turbulent flows in rivers, oceans and flumes [Voulgaris and Trowbridge (1997), Garcia et al (2005), Lane et al (1998), Thomson et al (2010), Richmond et al (2011)]. For this study, a Nortek vector (6-MHz) ADV was used to collect high temporal resolution data at a single point.…”

Section: Acoustic Doppler Velocimetry (Adv)mentioning

confidence: 99%

“…Before performing turbulence quantification from them, these ADV data were subjected to quality control procedures in order to remove noise and spurious data points. The quality control involved identifying the velocity data with low correlation and spikes [see Goring and Nikora (2002), Elgar and Raubenheimer (2001), Elgar et al (2005), Thomson et al (2010), Richmond et al (2011) for detail] and then replacing these spurious data points with the running average. Raw ADV velocity data (u, v and w ) and quality control velocity results are shown in Figure 3.1.…”

Section: Advmentioning

confidence: 99%

“…For FY-2011, these measurements were performed continuously for two weeks, in order to collect data during both neap and spring tides, as well as during diurnal tidal variations. The FY-2011 measurements were a follow-on to data collected at the same site in FY-2010 (Richmond et al (2011), Thomson et al (2010)). The ADV provided single point velocity measurements close to the lower extent of the rotor sweep of the MHK devices while the ADCP provided the velocity profile from the seabed up to the water surface.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Inflow Characterization for Marine and Hydrokinetic Energy Devices. FY-2011: Annual Progress Report

Richmond¹,

Durgesh²,

Thomson³

et al. 2011

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This document was printed on recycled paper. SummaryMarine and Hydro Kinetic devices (MHK) provide a way to harness energy from tides in costal regions. The Marrowstone Island site in Washington State is a potential location for installing MHK devices, since it experiences strong tides and associated currents. In order to quantify the effects of tidal currents on MHK devices, as well as the impact of MHK devices on the environment, a comprehensive study of tidal currents and flow is required. For this purpose, field studies were conducted at the Marrowstone Island site by the Pacific Northwest National Lab (PNNL) in collaboration with the Applied Physics Lab at the University of Washington (APL-UW). These field studies entailed Acoustic Doppler Velocimetry (ADV), Acoustic Doppler Current Profiler (ADCP) and Conductivity, Temperature and Depth (CTD) measurements. The instruments used for this study were mounted on a tripod which was deployed at the site from the R/V Jack Robertson provided by the APL-UW. The ADV acquired single point temporally resolved velocity data from 17-21 Feb 2011, at a height of 4.6 m above the seabed. In contrast, the ADCP acquired the velocity profile of the entire water column from a height of 2.6 m above the seabed up to the sea-surface in 36 bins, with each bin of 0.5 m size. The ADCP acquired data from 11-27 Feb 2011 at a sampling frequency of 2 Hz. CTD measurement data were acquired every 30 seconds at 1.85 m and 2.55 m above the seabed. Results from the ADV measurements showed that the flow is fully turbulent, with -5/3 slope in the inertial sub-range of the spectra. The ensemble average velocity profile obtained from ADCP measurements shows an agreement to both the log and power laws.iii

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Quantifying turbulence for tidal power applications

Cited by 44 publications

References 12 publications

Engineering analysis of turbulent flow measurements near Kuchinoshima Island

Engineering analysis of turbulent flow measurements near Kuchinoshima Island

A large scale model experimental study of a tidal turbine in uniform steady flow

Inflow Characterization for Marine and Hydrokinetic Energy Devices. FY-2011: Annual Progress Report

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