Structure of turbulent flow in EMEC's tidal energy test site

2009 ◽  
Vol 36 (5) ◽  
pp. 422-431 ◽  
Author(s):  
Emmanuel Osalusi ◽  
Jonathan Side ◽  
Robert Harris
Keyword(s):  
Turbulent Flow ◽  
Tidal Energy ◽  
Test Site

scholarly journals Winter and summer differences in probability of fish encounter (spatial overlap) with MHK devices

2018 ◽  
Vol 1 (1 (Aug)) ◽  
pp. 9-18 ◽  
Author(s):  
H. Viehman ◽  
T. Boucher ◽  
A. Redden
Keyword(s):  
Tidal Energy ◽  
Test Site ◽  
Energy Development ◽  
Bay Of Fundy ◽  
Natural Distribution ◽  
Spatial Overlap ◽  
Vertical Distributions ◽  
The Vertical Distribution ◽  
Distribution Of Fish ◽  
Tidal Stage

The likelihood of fish encountering an MHK device, and therefore the risk posed to fish, depends largely on the natural distribution of fish at tidal energy development sites. In temperate locations, such as the Bay of Fundy, seasonal changes in the environment and fish assemblage may alter the likelihood of fish encounters with MHK devices. We examined two one-month hydroacoustic datasets collected in winter 2015 and summer 2016 by an upward-facing echosounder deployed at the Fundy Ocean Research Center for Energy test site in the Minas Passage. Fish density was higher and less variable in winter than in summer, likely due to the presence of migratory vs. overwintering fish. The vertical distribution of fish varied with sample period, diel stage, and tidal stage. The proportion of fish at MHK device depth was greater, but more variable, in summer than in winter. Encounter probability, or potential for spatial overlap of fish with an MHK device, was < 0.002 for winter and summer vertical distributions. More information on the distribution of fish (horizontal and vertical), species present, fish sensory and locomotory abilities, and nearfield behaviours in response to MHK devices is needed to improve our understanding of likely device effects on fish.

Method for identification of Doppler noise levels in turbulent flow measurements dedicated to tidal energy

2013 ◽  
Vol 3-4 ◽  
pp. 52-64 ◽  
Author(s):  
Jean-Baptiste Richard ◽  
Jim Thomson ◽  
Brian Polagye ◽  
Jochen Bard
Keyword(s):  
Turbulent Flow ◽  
Tidal Energy ◽  
Noise Levels ◽  
Flow Measurements

Tidal Energy in Nova Scotia, Canada: The Fundy Ocean Research Center for Energy (FORCE) Perspective

2011 ◽  
Author(s):  
Douglas J. Keefe ◽  
Joseph Kozak
Keyword(s):  
Nova Scotia ◽  
Power Systems ◽  
Tidal Energy ◽  
Test Site ◽  
The United States ◽  
Research Center ◽  
Ocean Energy ◽  
Overhead Transmission Line ◽  
Marine Energy ◽  
Marine Current

Ocean energy developments are appearing around the world including Scotland, Ireland, Wales, England, Australia, New Zealand, Japan, Korea, Norway, France Portugal, Spain, India, the United States, Canada and others. North America’s first tidal energy demonstration facility is in the Minas Passage of the Bay of Fundy, near Parrsboro, Nova Scotia, Canada. The Fundy Ocean Research Center for Energy (FORCE) is a non-profit institute that owns and operates the facility that offers developers, regulators, scientists and academics the opportunity to study the performance and interaction of instream tidal energy converters (usually referred to as TISECs but called “turbines” in this paper.) with one of the world’s most aggressive tidal regimes. FORCE provides a shared observation facility, submarine cables, grid connection, and environmental monitoring at its pre-approved test site. The site is well suited to testing, with water depths up to 45 meters at low tide, a sediment -free bedrock sea floor, straight flowing currents, and water speeds up to 5 meters per second (approximately 10 knots). FORCE will install 10.896km of double armored, 34.5kV submarine cable — one for each of its four berths. Electricity from the berths will be conditioned at FORCE’s own substation and delivered to the Provincial power grid by a 10 km overhead transmission line. There are four berth holders at present: Alstom Hydro Canada using Clean Current Power Systems Technology (Canada); Minas Basin Pulp and Power Co. Ltd. with technology partner Marine Current Turbines (UK); Nova Scotia Power Inc. with technology partner OpenHydro (Ireland) and Atlantis Resources Corporation, in partnership with Lockheed Martin and Irving Shipbuilding. In November 2009, NSPI with technology partner OpenHydro deployed the first commercial scale turbine at the FORCE site. The 1MW rated turbine was secured by a 400-tonne subsea gravity base fabricated in Nova Scotia. The intent of this paper is to provide an overview of FORCE to the international marine energy community during OMAE 2011 taking place in Rotterdam, Netherlands.

scholarly journals On the Variation of Turbulence in a High-Velocity Tidal Channel

Energies ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 672 ◽  
Author(s):  
Charles Greenwood ◽  
Arne Vogler ◽  
Vengatesan Venugopal
Keyword(s):  
Maximum Flow ◽  
Tidal Energy ◽  
Test Site ◽  
Streamwise Velocity ◽  
Spatial And Temporal Variation ◽  
Turbulent Structures ◽  
Length Scales ◽  
Marine Energy ◽  
Flow Speeds ◽  
Turbulence Parameters

This study presents the variation in turbulence parameters derived from site measurements at a tidal energy test site. Measurements were made towards the southern end of the European Marine Energy Centre’s tidal energy test site at the Fall of Warness (Orkney, Scotland). Four bottom mounted divergent-beam Acoustic Doppler Current Profilers (ADCPs) were deployed at three locations over an area of 2 km by 1.4 km to assess the spatial and temporal variation in turbulence in the southern entrance to the channel. During the measurement campaign, average flood velocities of 2 ms−1 were recorded with maximum flow speeds of 3 ms−1 in the absence of significant wave activity. The velocity fluctuations and turbulence parameters show the presence of large turbulent structures at each location. The easternmost profiler located in the wake of a nearby headland during ebb tide, recorded flow shielding effects that reduced velocities to almost zero and produced large turbulence intensities. The depth-dependent analysis of turbulence parameters reveals large velocity variations with complex profiles that do not follow the standard smooth shear profile. Furthermore, turbulence parameters based on data collected from ADCPs deployed in a multi-carrier frame at the same location and time period, show significant differences. This shows a large sensitivity to the make and model of ADCPs with regards to turbulence. Turbulence integral length scales were calculated, and show eddies exceeding 30 m in size. Direct comparison of the length scales derived from the streamwise velocity component and along-beam velocities show very similar magnitudes and distributions with tidal phase.

Magnitude Estimation and Cross-Modal Matching of Lingual Vibrotactile and Auditory Sensation

1989 ◽  
Vol 32 (3) ◽  
pp. 698-702 ◽  
Author(s):  
Daniel Harris ◽  
Donald Fucci ◽  
Linda Petrosino
Keyword(s):  
Auditory Stimulus ◽  
Magnitude Estimation ◽  
Sensory Processing ◽  
Test Site ◽  
Systematic Investigation ◽  
Thenar Eminence ◽  
Stimulus Range ◽  
Psychophysical Scaling ◽  
Scaling Methods ◽  
Response Biases

The present experiment was a preliminary attempt to use the psychophysical scaling methods of magnitude estimation and cross-modal matching to investigate suprathreshold judgments of lingual vibrotactile and auditory sensation magnitudes for 20 normal young adult subjects. A 250-Hz lingual vibrotactile stimulus and a 1000-Hz binaural auditory stimulus were employed. To obtain judgments for nonoral vibrotactile sensory magnitudes, the thenar eminence of the hand was also employed as a test site for 5 additional subjects. Eight stimulus intensities were presented during all experimental tasks. The results showed that the slopes of the log-log vibrotactile magnitude estimation functions decreased at higher stimulus intensity levels for both test sites. Auditory magnitude estimation functions were relatively constant throughout the stimulus range. Cross-modal matching functions for the two stimuli generally agreed with functions predicted from the magnitude estimation data, except when subjects adjusted vibration on the tongue to match auditory stimulus intensities. The results suggested that the methods of magnitude estimation and cross-modal matching may be useful for studying sensory processing in the speech production system. However, systematic investigation of response biases associated with vibrotactile-auditory psychophysical scaling tasks appears to be a prerequisite.

An Introduction to Turbulent Flow

2000 ◽  
Author(s):  
Jean Mathieu ◽  
Julian Scott
Keyword(s):  
Turbulent Flow
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