scholarly journals Using coupled hydrodynamic biogeochemical models to predict the effects of tidal turbine arrays on phytoplankton dynamics

2016 ◽  
Author(s):  
Pia Schuchert ◽  
Louise Kregting ◽  
Daniel Pritchard ◽  
Graham Savidge ◽  
Björn Elsäßer
Keyword(s):  
Large Scale ◽  
Natural Variation ◽  
Tidal Energy ◽  
Phytoplankton Dynamics ◽  
Hydrodynamic Models ◽  
Energy Device ◽  
Active Radiation ◽  
Biogeochemical Models ◽  
Tidal Turbine ◽  
Turbine Arrays

Abstract. Coupled 2-dimensional biogeochemical and hydrodynamic models offer the opportunity to predict potential effects of large scale tidal energy device (TED) arrays on the local and regional phytoplankton dynamics in coastal and inshore environments. In an idealised environment the effect of TEDs on phytoplankton dynamics accounted for up to 25 % in phytoplankton concentrations, most likely associated with an increased residence time in an inshore basin. However, natural variation such as the intensity of photosynthetically active radiation had a larger effect on phytoplankton dynamics.

scholarly journals Using Coupled Hydrodynamic Biogeochemical Models to Predict the Effects of Tidal Turbine Arrays on Phytoplankton Dynamics

2018 ◽  
Vol 6 (2) ◽  
pp. 58 ◽  
Author(s):  
Pia Schuchert ◽  
Louise Kregting ◽  
Daniel Pritchard ◽  
Graham Savidge ◽  
Björn Elsäßer
Keyword(s):  
Phytoplankton Dynamics ◽  
Biogeochemical Models ◽  
Tidal Turbine ◽  
Turbine Arrays

scholarly journals Tidal current power effects on nearby sandbanks: a case study in the Race of Alderney

2020 ◽  
Vol 378 (2178) ◽  
pp. 20190503 ◽  
Author(s):  
Luke S. Blunden ◽  
Stephen G. Haynes ◽  
AbuBakr S. Bahaj
Keyword(s):  
Sediment Transport ◽  
Tidal Energy ◽  
Sand Wave ◽  
Sand Transport ◽  
Tidal Dynamics ◽  
Tidal Flows ◽  
Tidal Turbine ◽  
Turbine Arrays ◽  
Sediment Model

A validated numerical model of tidal flows and sediment transport around the Alderney South Banks was used to investigate the potential effects of large (300 MW) tidal turbine arrays at different locations in Alderney territorial waters. Two methods were used, firstly looking at hydrodynamic changes only and secondly modelling sediment transport over a non-erodible bed. The baseline hydrodynamic model was validated relative to ADCP velocity data collected in the immediate vicinity of the sandbank. Real-world sand transport rates were inferred from sand-wave migrations and agree favourably with sediment transport residuals calculated from model outputs. Outputs from the sediment model reproduced realistic morphological behaviours over the bank. Seventeen different locations were considered; most did not result in significant hydrodynamic changes over the South Banks; however, three array locations were singled out as requiring extra caution if development were to occur. The results provide a case for optimizing the array locations for twin objectives of maximizing array power and minimizing impacts on the sandbanks. This article is part of the theme issue ‘New insights on tidal dynamics and tidal energy harvesting in the Alderney Race’.

scholarly journals Turbulence and Wake Effects in Tidal Stream Turbine Arrays

2018 ◽  
Author(s):  
Martin Nuernberg ◽  
Longbin Tao
Keyword(s):  
Flow Field ◽  
Electricity Generation ◽  
Large Scale ◽  
Numerical Models ◽  
Turbulence Models ◽  
Ambient Flow ◽  
Wake Effects ◽  
Tidal Turbine ◽  
Turbine Arrays ◽  
Good Agreement

Electricity generation from tidal current can provide a reliable and predictable addition to a reduced carbon energy sector in the future. Following the deployment of the first multi-turbine array, significant cost reduction can be achieved by moving beyond demonstrator projects to large scale tidal turbine arrays. The interactions between multiple turbines installed in close proximity can affect the total electricity generation and thus require knowledge of the resulting flow field within and downstream of the array. Results are presented for experimental and numerical studies investigating the flow field characteristics in terms of velocity deficit and turbulence intensity in a staggered tidal turbine array section. Multiple configuration with varying longitudinal and transverse spacing between devices in a three-turbine array are tested. Comparison between numerical and experimental flow characteristics shows that open source numerical models with dynamic mesh features achieve good agreement and can be used for the investigation of array wake effects. The standard k–ω SST shows good agreement with experiments at reduced computational efficiency compared to higher order turbulence models (RSM). The importance of mixing with ambient flow is highlighted by identifying areas of significantly reduced velocity recovery within closely spaced arrays where ambient flow does not penetrate between adjacent wakes.

scholarly journals Experimental Study of Flow Field Characteristics in Tidal Stream Turbine Arrays

2016 ◽  
Author(s):  
Martin Nuernberg ◽  
Longbin Tao
Keyword(s):  
Flow Field ◽  
Large Scale ◽  
Water Channel ◽  
Experimental Studies ◽  
Energy Resource ◽  
Small Scale ◽  
Large Set ◽  
Flow Field Characteristics ◽  
Tidal Turbine ◽  
Turbine Arrays

Tidal currents at many locations around the world have great potential to be used as a large scale renewable energy resource in the future. For large tidal turbine arrays to be commercially viable, the interactions of large devices operating in a confined operating environment need to be understood to optimise the layout of arrays to maximise electricity generation. This study presents results from a comprehensive experimental investigation of the flow field characteristics within tidal turbine arrays across a number of array layout configurations and current velocities. Up to four small scale turbines were placed in a circulating water channel to investigate the effects of changing array configuration and wake interaction on the flow velocity and turbulence characteristics in small array layouts. Detailed account of the resulting flow field characteristics has been taken by particle image velocimetry measurements at a number of locations within the wake of the array thus providing a large set of instantaneous flow recordings for further analysis of flow features and wake characteristics. Results are shown for experimental studies of single, three and four turbine arrays and some preliminary comparison between experimental measurements and numerical results are made.

scholarly journals Experimental analysis of the shear flow effect on tidal turbine blade root force from three-dimensional mean flow reconstruction

2020 ◽  
Vol 378 (2178) ◽  
pp. 20200001 ◽  
Author(s):  
B. Gaurier ◽  
Ph. Druault ◽  
M. Ikhennicheu ◽  
G. Germain
Keyword(s):  
Turbine Blade ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Tidal Energy ◽  
Velocity Shear ◽  
Reconstruction Method ◽  
Mean Flow ◽  
Blade Root ◽  
Image Velocimetry ◽  
Tidal Turbine

In the main tidal energy sites like Alderney Race, turbulence intensity is high and velocity fluctuations may have a significant impact on marine turbines. To understand such phenomena better, a three-bladed turbine model is positioned in the wake of a generic wall-mounted obstacle, representative of in situ bathymetric variation. From two-dimensional Particle Image Velocimetry planes, the time-averaged velocity in the wake of the obstacle is reconstructed in the three-dimensional space. The reconstruction method is based on Proper Orthogonal Decomposition and enables access to a representation of the mean flow field and the associated shear. Then, the effect of the velocity gradient is observed on the turbine blade root force, for four turbine locations in the wake of the obstacle. The blade root force average decreases whereas its standard deviation increases when the distance to the obstacle increases. The angular distribution of this phase-averaged force is shown to be non-homogeneous, with variation of about 20% of its time-average during a turbine rotation cycle. Such force variations due to velocity shear will have significant consequences in terms of blade fatigue. This article is part of the theme issue ‘New insights on tidal dynamics and tidal energy harvesting in the Alderney Race’.

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