flow characteristics and energy potential in tsugaru strait toward tide and sea current power...
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Flow Characteristics and Energy Potentialin Tsugaru Strait toward Tide and Sea
Current Power Generation
by Makoto MIYATAKE
Institute of National Colleges of Technology, Hakodate National College of Technology
Department of Civil Engineering,Hakodate National College of Technology
Backgrounds Basic message
Previous Qualitative Knowledge
The seasonal water flow characteristics are one of important factors that need to consider for power generation in Tsugaru Strait.
The seasonal characteristics of water flow across Tsugaru Strait has been known, that is dominated by both tide and ocean current.
The interaction mechanism in-depth of tide and ocean current in four seasons has not been well understood.
View of Tsugaru Strait during Winter Storm Season
OpenHydro and EDF (France):16m diameter ×42MW each35 m water depthelectricity for 4000 homes
To clarify the current interaction mechanism relationship between tide and ocean current by using the numerical modeling after reproducing the observation results accurately.
Objectives
To investigate the variation characteristics of tide and ocean current through field observations of four seasons.
To estimate the energy potential based on the results of both field observations and numerical simulations.
20
25
303540455055606570
75
St.1
N
Toward Hakodate
ShiokubiHeadland
Hakodate City
Field Observations Setup
Transmission Frequency 300kHz
MaximumSetup Depth 260m
Maximum Thickness of Layer
0.2m~16.0m
MaximumNumber of Layer 128
contents spec
Specifications of ADCP
ObservationPeriods
Spring 18th/3/2013~18th/4/2013(31days)Summer 31st/7/2013~4th/9/2013(35days)Autumn 19th/10/2013~4th/12/2013(45days)Winter 4th/12/2013~20th/1/2014(47days)
ObservationLayers
Upper 23.3m from sea bottomMiddle 12.2m from sea bottomBottom 3.2m from sea bottom
ObservationTime Intervals 60min.(Obs. Duration 40min., Sampling 1s.)
Observation Site and Method
Relationship Between Multi-layer Velocity and Tide (Spring) Ve
loci
ty(c
m/s
)Ve
loci
ty(c
m/s
)Ve
loci
ty(c
m/s
)
Upper Layer
Middle Layer
Bottom Layer
Observation Dutation
Normalized Cross-Correlation Function
Upper LayerMiddle LayerBottom Layer
Nor
mal
ized
Cros
s-Co
rrel
ation
Fun
ction
Velo
city
(m/s
)
Time Lag(hr)
Tide Difference(cm)
(a) Relationship between Cross-Correlation and Time Lag
(b) Correlation of Tide Difference and Flow Velocity including 3hr Lags
UpperMiddleBottom
Tidal Current Ellipses of Principal Four Tidal Components
upper
middle
bottom
upper
middle
bottom
upper
middle
bottom
K1 O1 M2
S2
upper
middle
bottom
upper
middle
bottom
Composition
Dep
th(m
)
Dep
th(m
)D
epth
(m)
Dep
th(m
)
Dep
th(m
)
Water D
epth [m]
Longitude [deg]La
titud
e [d
eg]
50m
100m
300m
200m
Computation Range E140 - E141.383, N41.183 - N41.833
Mesh Scale( Dlon. x Dlat.)
30sec x 30sec
Mesh Scale( Vertical) 1.0m--15.0m
Time Step 10sec
Bottom Friction Slip-Boundary Condition
Start Time 15th/March 2013 00:00 (UTC)
Case # 1 2 3
Tidal Current
Tidal Current Velocity as Inflow Boundary Condition Given from TPXO7.2. ―
Ocean Current ―
Ocean Current Velocity as Inflow Boundary Condition Given from JAMSTEC FRA-JCOPE2
Numerical Simulations for Water Current
Specifications of CalculationComputation Area
Computation Cases
0
2
V
FVV
Dt
D
MITgcm(MIT General Circulation Model )
Same as Spring Obs.
Comparison Numerical Result with Observation Data
upper
middle
bottom
upper
middle
bottom
upper
middle
bottom
K1 O1 M2
S2
upper
middle
bottom
upper
middle
bottom
Composition
Dep
th(m
)
Dep
th(m
)D
epth
(m)
Dep
th(m
)
Dep
th(m
)
Orbit Radius [m
/s]
Longitude [deg]
Latit
ude
[deg
]
O1 1m/s
Orbit Radius [m
/s]
Longitude [deg]
Latit
ude
[deg
]
K1 1m/s
Orbit Radius [m
/s]
Longitude [deg]
Latit
ude
[deg
]
M2 1m/s
Orbit Radius [m
/s]
Longitude [deg]
Latit
ude
[deg
]
S2 1m/s
Black color: anticlockwise, Pink Color: clockwiseTidal Current Ellipse Distribution(Case 1; tidal current only)
Orbit Radius [m
/s]
Longitude [deg]
Latit
ude
[deg
]
O1 1m/s
Orbit Radius [m
/s]
Longitude [deg]
Latit
ude
[deg
]
K1 1m/s
Orbit Radius [m
/s]
Longitude [deg]
Latit
ude
[deg
]
M2 1m/s
Orbit Radius [m
/s]
Longitude [deg]
Latit
ude
[deg
]
S2 1m/s
Tidal Ellipse Current Distribution(Case 2;tidal+ocean current)Black color: anticlockwise, Pink Color: clockwise
residual current velocity [m/s]
Longitude [deg]
Latit
ude
[deg
]
1m/s
residual current velocity [m/s]
Longitude [deg]
1m/s
Case 1
Case 3
residual current velocity [m/s]
Longitude [deg]
Latit
ude
[deg
]
1m/sCase 2
Latit
ude
[deg
]
Residual Current Velocity Distribution
Case1: tidal current onlyCase2: tidal+ocean currentCase3: ocean current only
Density of Energy [kW
/m2]
Longitude [deg]
Latit
ude
[deg
]D
ensity of Energy [kW/m
2]
Longitude [deg]
Latit
ude
[deg
]D
ensity of Energy [kW/m
2]
Longitude [deg]
Latit
ude
[deg
]D
ensity of Energy [kW/m
2]
Longitude [deg]
Latit
ude
[deg
]
Case 1Case 1
Case 2Case 2
Depth Averaged Energy Potential Distribution
Duration average
Duration maximum
Duration average
Duration maximum
Brief Summaries
The SE water flow accompanied by periodic variations is constructed by combining the southeastward residual current with tidal current in direction of NW-SE.
The next step in this work are as follows.
The energy potential distribution estimated from the analysis results
indicates that the most appropriate location of power generation is
around the side of Shimokita Peninsula coast waters.
To verify the observation data in other seasons and clarify the seasonal variation of water current and the energy potential through the numerical simulation.