Hydrodynamic performance evaluation of a tidal turbine with leading-edge tubercles

Shi, Weichao; Rosli, Roslynna; Atlar, Mehmet; Norman, Rosemary; Wang, Dazheng; Yang, Wenxian

doi:10.1016/j.oceaneng.2016.03.044

Cited by 52 publications

(32 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Under the above circumstances, continuing the design and optimisation work on tidal turbine blades started by Wang et al (2007), the team in the Emerson Cavitation Tunnel (ECT), Newcastle University has recently initiated a new turbine blade study, by applying the leadingedge tubercles of humpback whale flippers to a tidal turbine (Shi et al, 2016a;Shi et al, 2016b). The tubercles have the potential to improve the performance of foils.…”

Section: Introductionmentioning

confidence: 99%

Cavitation observations and noise measurements of horizontal axis tidal turbines with biomimetic blade leading-edge designs

et al. 2016

Self Cite

View full text Add to dashboard Cite

This paper focuses on the study of cavitation and underwater noise performance of a biomimetically improved horizontal axis tidal turbine (HATT) with a leading edge design inspired by the tubercles on the pectoral fins of humpback whales. Systematic model tests were recently conducted and details of this test campaign together with the findings are summarised in the paper. Several full-scale tidal turbine application cases were studied to understand the full-scale operating conditions considering the characteristics of varied kinds of tidal energy devices, the varying wave height and the flood/ebb tide. A systematic test regime was then designed and conducted. A set of tidal turbines with different leading-edge profiles was manufactured and tested under different loading and hence cavitation conditions. During the tests, cavitation was observed and underwater noise level was measured in comparison with the cavitation and noise performance of a counterpart HATT without tubercles. The tested turbines displayed two main types of cavitation patterns independent of the tubercles. These were steady tip vortex cavitation and relatively intermittent cloud cavitation with a misty appearance. The leading-edge tubercles triggered the cavitation onset earlier for the tidal turbine but constrained the cavitation region to the trough between tubercles with a lesser extent on the blades. The noise performance was strongly related to the blade cavitation hence it was influenced by the leading-edge tubercles. While the turbine was working under the non-cavitating conditions the total noise level was similar to the background noise level. With the increase of the tip speed ratio the noise level was increased, while increasing blade pitch angle reduced the noise level due to lower blade loading. Cavitation inception and noise diagrams are provided as a database for future studies

show abstract

Section: Introductionmentioning

confidence: 99%

Cavitation observations and noise measurements of horizontal axis tidal turbines with biomimetic blade leading-edge designs

et al. 2016

Self Cite

View full text Add to dashboard Cite

show abstract

“…The biomimetic tubercles produce a higher induction factor, hence a lower velocity in the wake field, which result in higher power and thrust coefficients. A higher power was also measured in [16] at lower Tip Speed Ratios (TSRs), with respect to a tidal turbine with no tubercles. [14] It was also observed that the tubercles improve the starting performance of the device, by reducing the cut-in velocity.…”

Section: Applicationsmentioning

confidence: 97%

“…This was also confirmed by Shi et al [12], who also found that tubercled tidal turbine blades underwent cavitation earlier, but the misty type cloud cavitation was confined to the areas between the tubercles. The effect of leading edge tubercles on the performance of tidal turbine blades was extensively studied by several researchers, as in [12][13][14][15][16][17] . Grueber et al [17] carried out towing tank tests on a set of tidal [17] turbine blades, in order to quantify the effect of leading edge tubercles on the performance.…”

Section: Applicationsmentioning

confidence: 99%

An Investigation of the Effect of Biomimetic Tubercles on a Flat Plate

Marino

Atlar

Demirel

2019

Volume 7A: Ocean Engineering

Self Cite

View full text Add to dashboard Cite

This paper describes the investigation, by means of Computational Fluid Dynamics (CFD), of the effect of biomimetic tubercles on the hydrodynamics of a fully submerged flat plate. The application of these tubercles takes inspiration from the features of the humpback whale (Megaptera Novaeangliae). These huge marine mammals are capable of quick and agile movements in the water, despite their bulky bodies. Researchers investigated the causes of this ability by studying some peculiar somatic characteristics of these animals, in particular the tubercles on the leading edge of their pectoral fins. These tubercles were applied in the form of sinusoidal perturbations of the leading edge of wing profiles and foils, and they proved to cause a positive effect on the overall performance. The aim of this paper is to investigate another type of tubercles, which appear in the shape of bumps on the whales head. The effect of these tubercles has not been studied yet, and this paper presents a study on the fundamental phenomena they generate in the water flowing on the surface of a flat plate. The tubercles are modelled as axisymmetric sinusoidal bumps placed on the flat plate. Different combinations of these tubercles are studied, in order to assess what the effect of a single tubercle is, and how more tubercles interact when they are placed closed to each other, in different configurations (number of tubercles and relative position). In addition, a systematic study of the effect of a single row of tubercles spanning perpendicularly to the flow is carried out. The tubercles change systematically in amplitude and position along the plate. One further objective of this paper is to investigate if an optimised application of the biomimetic tubercles can lead to a drag reduction for the flat plate. Preliminary simulations show that the rows of tubercles interact with the boundary layer by modifying the pressure distribution, velocity and direction of the flow. The tubercles appear to generate vortices that are similar to those created by sinusoidal tubercles on the leading edge of foils, which tend to thin the boundary layer. A change in the total drag of the plate with tubercle is also noticeable, which even decreases from the baseline (flat plate with no tubercles), at certain combinations of position and tubercle amplitude.

show abstract

“…They will not be repeated once again in this paper in order to keep a concise context. In addition to these conventional blade design methods that were developed based on the fundamental theory of hydro-and aero-dynamics, the boom of designing efficient blade using biomimetic methods is also seen in recent years [11][12][13][14][15][16]. Biomimetic techniques take inspiration from natural designs.…”

Section: Introductionmentioning

confidence: 99%

“…A classic example is the humpback whale turbine blades, which adapt the whale's flipper and the flipper leading-edge tubercles to the design of blades [11,12]. Moreover, the positive contribution of the leading-edge tubercles to improving the energy capture efficiency of the blade has been validated in many numerical and experimental researches [13][14][15]. However, leading-edge tubercles can be made on the blade only in manufacturing process.…”

Section: Introductionmentioning

confidence: 99%

Numerical Research of the Effect of Surface Biomimetic Features on the Efficiency of Tidal Turbine Blades

2018

Self Cite

View full text Add to dashboard Cite

Horizontal-axis axial flow tidal current turbine is regularly used to exploit the kinematic energy in tidal currents. However, the scaling up of tidal current turbine is very difficult. This is because strong tidal current only exists in the underwater region close to water surface, which implies that scaling up by enlarging rotor size is not always applicable to tidal current turbines. Hence, scaling up by improving the energy capture efficiency of the tidal turbine blade becomes a plausible choice. For this reason, apart from the numerous researches based on conventional aerodynamic and hydrodynamic theories, improving efficiency by biomimetic method is attracting increasing interest in recent years. It has been proved that leading-edge tubercles have positive contribution to improving the efficiency of tidal turbine blade. However, leading-edge tubercles can be made on blade only in the manufacturing process, as the post-production of them is quite difficult. Thus, how to improve the energy capture efficiency of the existing blades becomes a challenging issue. To address this issue, numerical research of the effect of surface biomimetic features on blade efficiency is conducted in this paper. For the sake of simplicity, surface bumps are investigated in this preliminary research in order to obtain a basic understanding of the effect of surface biomimetic features. In the research, the influences of surface bumps on blade surface pressure and the ratio of lift to drag forces are investigated in different bump array scenarios and at different tidal current speeds and the angles of attack. The calculation results have shown that surface bumps do improve the ratio of lift to drag forces of the blade in spite of their array arrangement, the angle of attack and tidal current speed. This suggests that the energy capture efficiency of both new and existing blades can be further improved if appropriate biomimetic features are deployed on the blade surfaces.

show abstract

Hydrodynamic performance evaluation of a tidal turbine with leading-edge tubercles

Cited by 52 publications

References 11 publications

Cavitation observations and noise measurements of horizontal axis tidal turbines with biomimetic blade leading-edge designs

Cavitation observations and noise measurements of horizontal axis tidal turbines with biomimetic blade leading-edge designs

An Investigation of the Effect of Biomimetic Tubercles on a Flat Plate

Numerical Research of the Effect of Surface Biomimetic Features on the Efficiency of Tidal Turbine Blades

Contact Info

Product

Resources

About