Influence of surface waves on the hydrodynamic performance of a horizontal axis ocean current turbine

Tian, Wenlong; Ni, Xiwen; Mao, Zhaoyong; Zhang, Tianqi

doi:10.1016/j.renene.2020.04.127

Cited by 25 publications

(11 citation statements)

References 20 publications

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“…They are compared with the results without a support structure. In first place, it is seen that power and thrust coefficients are smaller in the shallow immersion than in the deeper configuration, a result that agrees with the observations of [18,37]. Such reduction of the coefficients is related with a stronger deformation of the free surface in the case of shallow immersion as it can be seen in Figures 8 and 9 below.…”

Section: Effect Of Free Surface and Support Structure On Performancesupporting

confidence: 85%

“…Moreover, the free surface deformation upstream is increased for both immersions when the structure is included in the model. For the deep tip immersion, the free surface exhibits little disturbance downstream from the rotor in the absence of the structure which suggests that the free surface effect on the rotor performance is marginal when the rotor is well below it, in agreement with the conclusions of [18,37]. The highest depression downstream on the free surface occurs for the 0.19D immersion when the structure is present, followed by a peak that is approximately equal for both deep and shallow immersions with the support structure.…”

Section: Wake and Free Surface Interactionssupporting

confidence: 79%

“…Significant deformation of the air-water interface can be observed at both tip immersions, especially in the vicinity of the support rod. Figure 8 shows the wake past the support structure, revealed by the vorticity isosurface, which could not be detected in the previous study of Yan et al [18] but is present in the recent work of [37]. As a comment, blade root vortices are observed in the results of [18], which can be attributed to the presence of a gap between the rotor and the support in the employed computational model.…”

Section: Wake and Free Surface Interactionsmentioning

confidence: 70%

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Numerical Investigation of the Performance, Hydrodynamics, and Free-Surface Effects in Unsteady Flow of a Horizontal Axis Hydrokinetic Turbine

2021

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This paper presents computational fluid dynamics (CFD) simulations of the flow around a horizontal axis hydrokinetic turbine (HAHT) found in the literature. The volume of fluid (VOF) model implemented in a commercial CFD package (ANSYS-Fluent) is used to track the air-water interface. The URANS SST k-ω and the four-equation Transition SST turbulence models are employed to compute the unsteady three-dimensional flow field. The sliding mesh technique is used to rotate the subdomain that includes the turbine rotor. The effect of grid resolution, time-step size, and turbulence model on the computed performance coefficients is analyzed in detail, and the results are compared against experimental data at various tip speed ratios (TSRs). Simulation results at the analyzed rotor immersions confirm that the power and thrust coefficients decrease when the rotor is closer to the free surface. The combined effect of rotor and support structure on the free surface evolution and downstream velocities is also studied. The results show that a maximum velocity deficit is found in the near wake region above the rotor centerline. A slow wake recovery is also observed at the shallow rotor immersion due to the free-surface proximity, which in turn reduces the power extraction.

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Section: Effect Of Free Surface and Support Structure On Performancesupporting

confidence: 85%

Section: Wake and Free Surface Interactionssupporting

confidence: 79%

Section: Wake and Free Surface Interactionsmentioning

confidence: 70%

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Numerical Investigation of the Performance, Hydrodynamics, and Free-Surface Effects in Unsteady Flow of a Horizontal Axis Hydrokinetic Turbine

2021

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“…Also, for this application, it is suggested to use air‐bladder‐like devices which can store gas or air and help in UIoT sensor node deployment. As shown in reference 21 by localization methods and techniques, these UIoT sensor nodes can determine their position and depth underwater. Range‐free techniques do not use range or bearing information 22 .…”

Section: Preliminariesmentioning

confidence: 99%

An efficient self‐deployment methodology for maximized coverage of mobile underwater sensor networks

Roy

2022

Int J Communication

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SummaryA well‐optimized and well‐performed communication network protocol is necessary to build successful underwater acoustic sensor networks (UWASNs). But for wired and wireless communication, medium access control (MAC) has a great effect on network performance and optimization. But unlike land‐based MAC protocols, underwater MAC protocols come with various challenges and issues like high propagation delay, limited bandwidth for communication signals, large attenuation in network signals, and the high noise level in signals. It is very challenging to build a well‐optimized underwater MAC protocol. Also, in UWASN, sensor nodes are generally divided into sub‐network parts to reduce the propagation delay of data signals. But this creates the problem of non‐uniform traffic load in sensor nodes. So, considering these issues, dynamic hold time MAC (DHT‐MAC) protocol is proposed here. In this protocol, depending on the distance from the central node, sensor nodes are divided into two sub‐network zones (parent node and child node). Depending on the traffic load and propagation delay, the child nodes can change their respective parent nodes dynamically. Advantage of the proposed method is that, if any of the parent nodes stops working, the child node will connect to the nearest parent node. When collecting the data signals, it has been observed that child nodes have a light traffic load compared to parent nodes. So dynamic cooperative transmission MAC (DCT‐MAC) protocol which is a contention‐based MAC protocol has been used in child nodes and as parent nodes have high traffic load, reservation‐based MAC protocol has been used.

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“…Faktor-faktor hidro-oseaonografi seperti gelombang, arus laut dan pasang surut sangat berpengaruh terhadap kondisi di suatu perairan (Indrayanti et al, 2014). Penelitian mengenai gelombang air laut sangatlah beragam seperti yang telah dilakukan Duan et al (2019), Tian et al (2020) dan Wang et al (2020). Arus laut (sea current) adalah perpindahan massa air dari satu tempat menuju tempat lain, yang disebabkan oleh berbagai faktor seperti gradien tekanan, hembusan angin, perbedaan densitas, atau pasang surut (Tanto et al, 2017) dan salah satu aspek oseanografi yang penting untuk mengetahui hidrodinamika dari suatu perairan adalah pola pergerakan arus.…”

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Karakteristik Arus Laut Di Pelabuhan Pantoloan Kota Palu Sulawesi Tengah

Wahyuni

Ningsih²,

Rahmaniah³

2020

TEKNOSAINS

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Port construction at Pantoloan has influenced the condition of port and its environment. The hidro-oceanography process has influenced the condition of water, especialy to the current. This research was aimed to know the characteristic of current at Pantoloan, Palu, Central Sulawesi. The method used in this research was the measurement of current using a Floater. Data analysis of the floater current and position or coordinates of the floater were recorded on GPS. The results showed that the average of current velocity at high tide at the study site was 0.176 m/s with 221° to the to the Southwest and the average of the current speed at low tide was 0.178 m/s with 310° from the north to the northwest. Current speed at low tide is relatively weak compared to current speed at high tide.

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Influence of surface waves on the hydrodynamic performance of a horizontal axis ocean current turbine

Cited by 25 publications

References 20 publications

Numerical Investigation of the Performance, Hydrodynamics, and Free-Surface Effects in Unsteady Flow of a Horizontal Axis Hydrokinetic Turbine

Numerical Investigation of the Performance, Hydrodynamics, and Free-Surface Effects in Unsteady Flow of a Horizontal Axis Hydrokinetic Turbine

An efficient self‐deployment methodology for maximized coverage of mobile underwater sensor networks

Karakteristik Arus Laut Di Pelabuhan Pantoloan Kota Palu Sulawesi Tengah

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