Laboratory study on the effects of hydro kinetic turbines on hydrodynamics and sediment dynamics

Ramírez-Mendoza, Rafael; Amoudry, Laurent O.; Thorne, Peter D.; Cooke, Richard; McLelland, Stuart J.; Jordan, Laura-Beth; Simmons, S.; Parsons, D.; Murdoch, L.

doi:10.1016/j.renene.2018.05.094

Cited by 17 publications

(5 citation statements)

References 21 publications

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“…In terms of the flow, a Re=10 6 is expected in real dimensions. Taking into account a median grain size of about 355 µm, corresponding to the used sand, and the friction velocity reported in Ramírez-Mendoza et al (2018), the resulting Rouse number of ∼2.6 indicates bed load transport which is also expected in a real TST deployment. Therefore, it is considered that the resulted scour and deposition in the near wake area found in the present investigation may develop at full scale.…”

Section: Discussionmentioning

confidence: 78%

“…Even though there is a transverse asymmetry in the sediment bed prior to introducing the TST, it is smaller that differences due to the presence of the TST. This effect is likely due to some imperfections of the initial sediment bed since there was not important cross-stream differences in the flow (see figure 13 in Ramírez-Mendoza et al, 2018). A significant rearrangement of the sediment bed is clearly seen after the installation of the modelled TST (Fig.…”

Section: Sediment Dynamicsmentioning

confidence: 91%

“…This is particularly the case in regions where the boundary layer occupies most of the water column due to fast-moving tidal currents and relatively shallow water depth (Prandle, 1982). Wakes may also interact with the sediment bed, resulting in modifications of the boundary layer (Möller et al, 2016), the wake itself (Chamorro et al, 2013), and the response of sediments (Hill et al, 2014(Hill et al, , 2016Ramírez-Mendoza et al, 2018). These changes can then lead to altered erosion and deposition patterns downstream of turbines or arrays, which may in turn affect the wake structure, impacting the efficiency of TSTs downstream and the stability of their foundations.…”

Section: Introductionmentioning

confidence: 99%

“…Characterising turbine wakes has relied on laboratory experiments (e.g., Myers and Bahaj, 2010;Stallard et al, 2015;Tedds et al, 2014;Stallard et al, 2015) and numerical modelling using computational fluid dynamics (e.g., Harrison et al, 2010;Daly et al, 2013;Batten et al, 2013). These studies have evolved from experiments with actuator disks (e.g., Myers and Bahaj, 2010) to experiments with multiple three-bladed turbines (e.g., Stallard et al, 2013), experiments with turbines interacting with a bottom boundary layer (e.g., Stallard et al, 2015;Möller et al, 2016;Simmons et al, 2018), and experiments including mobile sediment beds (e.g., Hill et al, 2014Hill et al, , 2016Ramírez-Mendoza et al, 2018). Computational fluid dynamics models have been applied to the study of TSTs from the use of homogeneous flows (e.g., Mason-Jones et al, 2013) to the inclusion of vertical profiles and waves (e.g., Tatum et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

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Asymmetric effects of a modelled tidal turbine on the flow and seabed

Ramírez-Mendoza

Murdoch²,

Jordan³

et al. 2020

Renewable Energy

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The extraction of power from the flow of water has become an important potential source of clean energy. In spite of significant interest in the interaction between energy extraction devices and water currents, comparatively little work has focused on flow asymmetry. Indeed, unusual wake behaviour and limits of turbine array efficiency have typically been attributed to boundary effects rather than the particular turbine geometry. The aim of the present study was to reveal the asymmetries in the hydrodynamic wake and the interactions with the sediment bed due to the presence of a hydrokinetic turbine. We combined:(i) computational fluid dynamics simulations; (ii) optical flow measurements from a series of flume experiments above a fixed rough bed; and (iii) acoustic measurements from a further series of flume experiments above a mobile sand bed. Results showed flow asymmetry due to the presence of the rotor which appeared to be related to the development of the wake and potentially to the gyre of the blades. Suspended sediments in the flume also exhibited asymmetrical characteristics due to the flow asymmetry. This imbalance in the flow field and sediment transport may decrease energy extraction efficiency in turbine arrays and also could have important environmental consequences.

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Section: Discussionmentioning

confidence: 78%

Section: Sediment Dynamicsmentioning

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Asymmetric effects of a modelled tidal turbine on the flow and seabed

Ramírez-Mendoza

Murdoch²,

Jordan³

et al. 2020

Renewable Energy

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“…The presence of Marine Hydrokinetic (MHK) devices induces changes in hydrodynamic conditions, affecting bed shear stress, and subsequently influencing sediment transport, both in near-field and far-field environments. Prior investigations have examined the morphological responses to MHK devices and arrays, employing both experimental [18] and numerical [19,20] approaches.…”

Section: Mhk Morphodynamic Impactsmentioning

confidence: 99%

Modeling Morphodynamic Impacts and Optimization of Marine Hydrokinetic Arrays in Shallow Offshore Environments

Moghadam,

Ortiz

2023

Water

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Marine hydrokinetic (MHK) devices hold the promise of expanding renewable energy production by tapping into the power of waves and currents for electricity generation. However, these devices remain in the developmental stage, necessitating research to understand their environmental impacts, lower operational costs, and prevent equipment failures. In this study, we investigate various MHK array configurations to gain insights into their effects on wave patterns, water flow, and sediment conditions, considering both short-term and long-term morphodynamic changes under average and extreme conditions in shallow offshore environments. Our objectives encompass understanding the influence of mean and extreme environmental conditions on MHK devices, evaluating their impact on the bathymetry of the ocean floor, and exploring the role of different array configurations in morphodynamic evolution. Our findings, based on modeling these devices as static lumps, reveal that sediment erosion downstream of MHKs increases by 50% after one year of average conditions. When accounting for the absorption of 30% of the energy by MHK devices, downstream sediment deposition surges by almost 125%. Moreover, alterations in MHK arrays, such as spacing, size, and number, result in noticeable changes in sedimentation magnitudes during storm conditions. While long-term mean wave conditions have minimal effects on sedimentation, extreme wave conditions, akin to large storm events, bring about significant alterations in ocean floor bathymetry, potentially leading to costly maintenance of the MHK arrays. Our research provides a valuable framework for site analysis, enabling the estimation of maintenance needs and the optimization of array configurations to minimize sedimentation-related issues.

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