Static Torque Coefficient Research Articles

Numerical Model Parameters Choice of Helical Savonius Wind Rotor: CFD Investigation and Experimental Validation

Electrical power is essential for human beings welfare. The available wind as a clean and renewable source of energy has whetted extensive interest over decades. Savonius vertical axis wind rotor as an energy converter has the merit of being adequate for specific implementations owing to its lower cost and independency on wind direction. From this perspective, multiple studies have been conducted to boost its efficiency. This research work emphasizes on the helical Savonius wind rotor (HSWR). The basic objective is to investigate the impact of selecting the numerical model parameters on its aerodynamic and performance characteristics. Experimental tests were realized with a 3D printed HSWR in a wind tunnel. The experimental performances in terms of power, static and dynamic torque coefficients were addressed. Next, a numerical study was undertaken through Ansys Fluent 17.0 software. Grid, turbulence model and rotating domain size tests were examined. Good accordance was obtained, which validated the numerical model with an averaged error of 5%. The maximum power coefficient proved to be equal to 0.124 at a tip speed ratio of 0.73 and 0.1224 at a tip speed ratio of 0.69, respectively, numerically and experimentally

Performance of Savonius Wind Turbine Affected by Circular Cylinder Beside Advancing and in front of Returning Blade: Experimental Method

This study investigates the influence of circular cylinders positioned beside the advancing blade and in front of the returning blade on the performance of a Savonius wind turbine. The experimental method focuses on assessing how these cylinders affect the turbine’s efficiency and self-starting capability. Various distances between the cylinders and the turbine blades (S/D = 1.4) and different cylinder positions (Y/D = 1.27, 1.32, 1.37, 1.42, 1.51, 1.61, 1.71, 1.82, 2.00) were explored. Tests were conducted under constant speeds corresponding to Reynolds numbers of Re = 120,000 and 150,000. Preliminary findings of all various distances indicate a significant improvement in turbine performance, particularly in enhancing self-starting ability, when using these disturbance cylinders compared to conventional designs. Specifically, the configuration with cylinders positioned at S/D = 1.4 and Y/D = 1.51 demonstrated the most promising results, showing the static torque coefficient a 48% increase in performance at a wind speed of 6 m/s and a remarkable 78% increase at 7 m/s. These results highlight the potential of utilizing circular cylinders strategically around Savonius wind turbines to optimize their performance and operational efficiency.

One-way fluid structure interaction analysis of a static savonius hydrokinetic turbine under different velocity and surface roughness with different blade materials

Hydrokinetic turbines are prone to a harsh hydrodynamic environment with intricate vortical flows that elevate the probability of failure. The degradation of the blade surface caused by corrosion can impact the blade's hydrodynamic and the structural performance. This paper reports a one-way three-dimensional fluid-structure interaction simulation to analyse the performance of a static Savonius hydrokinetic turbine at varying rotor positions, with different surface roughness and water velocities, in terms of coefficients of static torque, static torque, stresses, and blade deformation. The simulations revealed that the optimum position for the highest coefficient of static torque was at 15° (Cst = 0.30) in reference to the water flow. Increasing the water velocity from 0.4 ms−1 to 0.84 ms−1 improved the turbine static torque due to an increase in the kinetic energy. However, the presence of surface roughness has deterioration effects on the static torque coefficient due to a delayed separation which causes a drag reduction. The simulation predicted no structural failure at 0.4 ms−1 and 0.84 ms−1, but varying materials exhibited varying maximum principal stress and deformation, highlighting the significance of the early development of materials selection process. The maximum von Mises stress and deformation was obtained when the turbine is resting at 45° for aluminium blade (σ = 1.05 MPa, ε = 5.6e−4 mm). The results of this study indicate suitable materials from a hydrodynamic and material perspectives for the construction of the Savonius hydrokinetic turbine, which can be implemented in the design process to potentially save cost and minimize turbine downtime.

Wind tunnel experimental study on static aerodynamic performance of SB-VAWT without intermediate support axes

Wind power generation is considered an effective way for ships to harness wind energy, and the aerodynamic characteristics of wind turbines determine wind energy utilization and efficiency. However, traditional vertical axis wind turbines have intermediate shafts and support rods, which result in large negative effects in the research of the wind turbine aerodynamic characteristics. To address this issue, a Straight-Bladed Vertical Axis Wind Turbine (SB-VAWT) without intermediate support axes is proposed. The turbine can flexibly change the number of blades, rotor diameter, and installation position of blades. The static aerodynamic performance of the wind turbine with different combinations was tested in a wind tunnel laboratory at 10 m/s. The results show that the radius of the wind turbine has a greater effect on the drag coefficient for the same number of blades, with an inverse relationship between the drag coefficient and radius, and a positive association between lift coefficient, static torque coefficient, and radius. The drag coefficient is proportional to the number of blades at the same radius, while the static torque coefficient is inversely proportional to the number of blades. According to the results, placing the initial location in the azimuth range between 30° and 50° can obtain the maximum initial starting torque. Moreover, a wind turbine with a radius of 16 cm can achieve a higher average torque. Changes in the number of blades can significantly impact turbine properties, resulting in wind turbines with distinct features.

Enhancing vertical axis wind turbine efficiency through leading edge tubercles: A multifaceted analysis

This research paper aims to investigate the impact of leading edge tubercles (LET) on the performance of hybrid vertical axis wind turbine (VAWT). The study involves both experimental and computational analysis of a novel hybrid VAWT configuration. The proposed VAWT design is characterized by a high power coefficient and self-starting capability. To provide a basis for comparison, an existing hybrid VAWT without tubercles and a conventional H-Rotor Darrieus design were also examined. The findings indicate that the proposed hybrid VAWT achieved the highest power coefficient (Cp) of 0.475 at a tip speed ratio (TSR) of 3. Furthermore, the proposed wind turbine demonstrated superior Cp values at both low TSRs (1 to 2.1) and high TSRs (4.1 to 5) compared to the existing hybrid VAWT and the H-Rotor Darrieus turbine. The positive static torque coefficient (Cts) values observed at all azimuths, with a maximum value of 0.319, highlight the self-starting capability of the proposed hybrid wind turbine. The enhanced power coefficient and the ability to harness wind energy even at low wind speeds make the proposed hybrid wind turbine suitable for a wide range of power projects, from small to large-scale. This approach offers a means to determine the optimal design configuration for a hybrid VAWT and facilitates a detailed analysis during the early design stages, along with its high-fidelity characteristics.

Wind tunnel test and numerical analysis of wooden-bladed Darrieus wind rotor at low wind speed conditions

The present study aims to conduct wind tunnel tests and numerical analyses to comprehensively assess the performance of wooden-bladed Darrieus wind rotors, specifically focusing on their behavior at low wind speeds. Limited investigation exists on the aerodynamic behavior of wooden-bladed Darrieus wind rotors under low wind speed conditions, necessitating comprehensive analysis to understand their performance characteristics and address this research gap. The present study is undertaken to address this gap. In addition, the paper also presents airfoil and blade material selection and fabrication of the rotor. The study is conducted on the NACA 0018 airfoil profile of the blades at low wind speeds of 4 and 6 m/s, commonly encountered in urban areas. The wind tunnel tests measure various rotor performance parameters such as the Static torque coefficient (Cts) and Power coefficient (Cp). At the same time, numerical simulations are used to study the flow behavior around the rotor blades. The Cts of the rotor is calculated at 12 different azimuthal positions between 0° to 360°. The Cp of the rotor is calculated at different tip speed ratios (λ). The present rotor exhibited maximum Cts of 0.64 and 0.66 and maximum Cp of 0.132 (at λ = 1.26) and 0.141 (at λ = 1.29) for 4 m/s and 6 m/s, respectively. Finally, it can conclude that the constructed wooden Darrieus rotor is working positively at low wind speeds, and the results may be used to develop wooden wind turbines for small-scale power generation.

Power performance and self-starting features of H-rotor and helical vertical axis wind turbines with different airfoils in turbulence

Wind tunnel tests were conducted to systematically assess the aerodynamic performance of both H-rotor and helical vertical axis wind turbines (VAWTs) in smooth and turbulent flows. The effects of airfoil section and pitch angle β on the power and self-starting performance were examined for both types of turbines. The helical turbine had a wider operating range of tip speed ratios (TSR λ) and much lower power performance than its H-rotor counterpart. This phenomenon was attributed to the flow deflection of helical blades due to their three-dimensional features, as well as that dynamic stall of a helical blade would not occur simultaneously for all blade elements. The helical turbine did not exhibit notably improved self-starting performance despite of the high manufacturing cost. Moreover, the start-up process was analyzed by using the static torque coefficient CT of both single-bladed and three-bladed turbines. It was found that turbulence intensity exercised a significant impact on CT. Turbulence would cause serious fatigue issues for H-rotor turbines and change the driving mechanism of helical turbines though it enhanced the self-starting performance. Recommendations were finally provided for the design of VAWTs in built environments.

Experimental investigation of solidity and blade profile effects on H-Darrieus wind rotor: Performance and self-starting analysis

The present study investigates the impact of rotor solidity and blade profile on the self-starting characteristics and performance of H-Darrieus wind rotors (H-rotors) through subsonic wind tunnel experiments. Three symmetrical (NACA 0018) and three unsymmetrical (NREL S823) H-rotors were analyzed to determine the coefficient of static torque (Cts) and coefficient of power (Cp) across three solidities (σ = 0.25, 0.3, and 0.35) and two free stream wind speeds (Uf = 6 and 8 m/s). The findings revealed that the NREL S823-bladed H-rotor outperformed the NACA 0018-bladed H-rotor, displaying 13% and 11% higher Cts values at σ = 0.25 (Uf = 6 and 8 m/s), 9% and 9% at σ = 0.3 (Uf = 6 and 8 m/s), and 13% and 11% at σ = 0.35 (Uf = 6 and 8 m/s). The NREL S823-bladed H-rotor achieved a maximum Cp of 0.197 at σ = 0.3 and Uf = 8 m/s, which is 6% higher than the maximum Cp obtained by the NACA 0018-bladed H-rotor. Furthermore, the trend of maximum Cp values for both H-rotors followed the order of Cp, max σ = 0.25 < Cp, max σ = 0.3 > Cp, max σ = 0.35. Based on the experimental findings, it is inferred that the NREL S823-bladed H-rotor with a solidity of 0.3 is suitable for small-scale wind turbines.

Experimental investigation and analysis of proposed hybrid vertical axis wind turbine design

In this research, an experimental and computational analysis of a novel hybrid vertical axis wind turbine (VAWT) arrangement has been performed. We suggest an innovative VAWT design that has a high power coefficient and self-starting capability. The inner side of the proposed hybrid system has been integrated with the H-rotor turbine with cambered blades, which demonstrates strong self-starting capabilities at various azimuths. Three NACA0018 airfoil blades are mounted on the outside of the proposed hybrid wind turbine, while three DU 06-W-200 airfoil blades are installed on the inside. Based on a similarity analysis, a scaled-down model was developed, and performance characteristics such as the output power, power coefficient ([Formula: see text]), dynamic torque coefficient ([Formula: see text]), and static torque coefficient ([Formula: see text]) were determined. An existing hybrid VAWT and a typical H-rotor Darrieus design were also examined for comparison. The highest [Formula: see text] for the proposed hybrid design was found to be 0.486 at a tip speed ratio (TSR) of 3, while the H-rotor Darrieus’ maximum value was 0.42 at a TSR of 2.62 and the existing hybrid VAWT’s value was 0.41 at a TSR of 2.5. Positive [Formula: see text] values at all azimuths demonstrate that the proposed hybrid wind turbine can start entirely on its own. In comparison to the existing H-rotor and hybrid VAWT, this novel hybrid system has shown enhanced performance parameters ([Formula: see text], [Formula: see text], [Formula: see text], output power) by around 11%–13% over a wide range of wind speeds.

A numerical and experimental study on the performance of a conventional H- Darrieus wind rotor with auxiliary blades

This article presents a numerical and experimental investigation of the performance of a conventional H- Darrieus rotor (Known as H-rotor) equipped with auxiliary blades. The study aims to improve the starting ability and the power coefficient (Cp) of the H- rotor. A numerical model is developed using the computational fluid dynamics (CFD) software ANSYS Fluent to simulate the flow field around the rotor. The model is validated with experimental results obtained from a laboratory-scale test rig. From the pressure contour and flow streamline analysis, it can conclude that the auxiliary airfoil serves as a boundary control device, reducing the amount of flow separation and turbulence around the main blade, which further improves the performance of the H-rotor. From the experimental results, the maximum static torque coefficient (Cts) and Cp of the modified H- rotor were found to be 0.11 and 0.18, which is 84% and 22% higher than the conventional H-rotor, respectively. The study concludes that the use of auxiliary blades can enhance the performance of the H-rotor and make it a more competitive option for harnessing wind energy in low-wind speed regions. The findings of this study could have significant implications for the development of small-scale wind turbines.

A comprehensive review on design and development analysis and blade material selection of helical Savonius rotor

The helical Savonius rotor (HSR) is used as green energy generation. The accurate design of HSR is essential before installing any wind farm in a region. It has been widely employed that positive static torque coefficients of helical Savonius rotor are higher compared to conventional semicircular rotor stated by several researchers. The reason is behind that the formation of secondary vortex of fluid. It is leading by vertical vortex flow, which passes over the curve surface and creates drag force. Still now, various design have been proposed to meet peak power output through optimum geometry parameters like blade profile design, aspect ratio and overlap ratio. The selection of blade material is also the influencing parameter to improve the starting torque of the rotor. In this regards present paper is aim to study the details experimental, numerical, and analytical review on HSR and selection of blade material with minimum production cost.

Experimental analysis of hybrid VAWT and the effect of semi-cylindrical attachment to the trailing edge

Vertical axis wind turbines (VAWTs) work efficiently in low wind speed regions and varying wind directions like urban environments due to their omnidirectional capability. The current study examines experimentally the performance of the H-Darrieus VAWT having NACA 0018 airfoil by use of semi-cylindrical attachments at the trailing edge and hybridization using two bladed S-Savonius rotor with zero overlap conditions. The rotor's static torque and dynamic performances are investigated at a low wind speed of 4 m/s. The results show that the semi-cylindrical attachment increases the range of positive static torque. The static torque of Darrieus with attachment at 90° inside is more consistent, which enhances the starting capability of the Darrieus turbine with a static torque coefficient of 0.031, which is 29.7 % higher than a simple Darrieus turbine. The hybrid configuration shows maximum dynamic torque only at the 90° azimuthal position. The power coefficient of all configurations with attachments is lower than simple Darrieus due to drag created by attachments. The power coefficient value of 0.03 for hybrid configuration is the highest, with a wide range of tip speed ratio (TSR).

Effect of surface roughness and blade material on the performance of a stationary Savonius wind turbine under different operating conditions

The Savonius wind turbine is a vertical-axis wind turbine invented in 1930s consisting of a cylindrical drum with semi-circular blades attached to the drum. It is popular for its simple design, low costs, and self-starting ability, making it feasible for rural areas. As a rotating device, the blade is considered an important component of the Savonius turbine because it captures energy from an omni-directional wind flow and converts it into mechanical/electrical energy. Blade corrosion can cause a surface degradation which affects the blade's aerodynamic and structural performance. The relation between surface roughness and turbine performance has been addressed in various studies; however, most of these studies focused on horizontal-axis wind turbine. This study analyzed the performance of a static Savonius turbine using a three-dimensional (3D) computer simulation at different blade angle positions through a one-way fluid–structure interaction in terms of static coefficients, von Mises stresses, and deformation with different surface roughness at different wind velocities. The simulation reveals that the position with highest static torque coefficient is when the turbine is resting at 15° with respect to the flow direction. The flow velocity increases the performance; however, the surface roughness deteriorates the flow and decreases the static coefficient. The simulation herein predicts no structural failure, but different materials exhibit different maximum stress and deformation showing the importance of material selection in the turbine blade development. The findings from this study helps to identify a suitable material for the development of the Savonius turbine from a material point of view to minimize turbine downtime and potentially save cost.

Experimental study on the characterization of the self-starting capability of a single and double-stage Savonius turbine

The Savonius hydrokinetic turbine is a viable alternative for rural electrification despite its relatively low power coefficient. There are many ways to improve power performance, including the use of multiple-stage turbines. Although many studies have investigated the effects of multi-staging, few have captured their effect on three performance parameters combined: power efficiency, flow structure, and self-starting capability. Therefore, the current study explored and analyzed the extent of these parameters using a multi-stage conventional Savonius turbine in a wind tunnel facility with a varying flow speed of 5 m/s to 9 m/s. The findings suggested that adding a stage increased the power coefficient to a maximum of 138% at 5 m/s, but reached a plateau as the wind speed increased to 9 m/s. The double-stage was discovered to reduce the self-starting speed of the turbine at all rotor angles for self-starting capabilities. The coefficient of static torque results indicated that the maximum static torque for the single and double-stage configurations occurred at 45° and 45°/135° rotor angles, respectively. The qualitative study revealed that the double-stage turbine has a larger wake size at higher wind speeds, resulting in a reduced wake intensity at the rear side of the rotor. The reduced torque variation caused by the additional stage has improved the overall performance of the turbine, making the double-stage configuration more preferable than the single-stage, particularly for low speed, high depth, and narrow river applications.

Parametric study and Multi-Objective optimization of a ductless Archimedes screw hydrokinetic Turbine: Experimental and numerical investigation

Aiming to prolong the duration of detection equipment deployed in deep water, a new type of hydrokinetic turbine with good self-starting ability should be developed to harness low-speed current energy in such deep-water scenarios. In this study, a novel ductless Archimedes screw turbine is proposed to improve the system’s startup performance for low-speed current applications. An experimentally verified numerical method was used to investigate the parametric sensitivity of several key geometrical parameters. Strong interaction effects between the lead angle and number of turns were observed. The turbine performance enhancement by increasing the number of turns can only be achieved at a large lead angle. A tradeoff between the lead angle and number of turns is necessary for the optimization design of the ductless Archimedes screw turbine. Multi-objective optimization was performed on the ductless Archimedes screw turbine to improve its self-starting ability and power coefficient by using the central composite design, the radial basis function neural network, and the non-dominated sorting genetic algorithm. Water flume experiment results showed that the maximum power coefficient and static torque coefficient of the optimized ductless Archimedes screw turbine can be improved by 36.7% and 143%, respectively, with respect to the initial design. These results indicate ductless Archimedes screw turbines are suitable for low-speed current applications in deep water.

Enhancing Performance of Small Capacity Horizontal Axis Wind Turbine Using Grooved Linearized-Chord Blades

Abstract In the current article, E216 airfoil blades with linearized chord of a small-scale horizontal axis wind turbine are numerically investigated to enhance the performance of the turbine. The blade is modified by including grooves on its suction side. Three-dimensional Reynold’s averaged Navier–Stokes (RANS) simulations are performed with Shear Stress Transport k–ω as a turbulence model. The computed power-coefficient results are first validated with previous measurements by the present authors on a wind turbine of 1 m rotor diameter at two wind speeds of 6 and 8 m/s. Another validation with measurements from the literature is performed via comparison of the pressure-coefficient distribution along surfaces of E216 airfoil at an angle of attack of 6 deg. Based on the successful computation, six different rotor models are numerically investigated with different numbers and locations of grooves created along the blade length, from the hub to the tip region, on the blade suction side. The lift and drag coefficients are compared for the different simulated rotor models. Furthermore, the torque coefficient, thrust coefficient, and static torque coefficient are obtained for the simulated models. It is found that the best-simulated configuration is Model 1 having one groove at 80% blade-chord length from the leading edge, with a maximum power coefficient of 0.429 at a tip-speed ratio of 4.75. The aerodynamic performance of the blades is strongly affected by the groove on the suction surface. The results show that Model 1 blade reduces the generated mean-axial force and its vibration frequency on the rotor.

Study on Aerodynamic Characteristics of a Savonius Wind Turbine with a Modified Blade

In order to improve the static start-up problem of Savonius wind turbines, a Savonius wind turbine with a modified blade is proposed. It was obtained by twisting the half-cylindrical blades of the basic Savonius wind turbine by 70°. The aerodynamic performance of the wind turbine before and after the modification was compared. Firstly, the static torque coefficient of two wind turbines at different azimuth angles were obtained by means of three-dimensional numerical simulation. The static flow field around the wind turbine was analyzed. Then, the output power and speed characteristics of a spiral Savonius wind turbine under different incoming wind speeds were evaluated in the wind tunnel. The results show that, compared with the Savonius wind turbine with half-cylindrical blades, the spiral wind turbine could start at any azimuths in one rotation cycle. The reverse torque was eliminated. The static torque coefficient fluctuation range was reduced by 10%. The start-up performance was effectively improved. This investigation could provide guidance for the improvement of start-up characteristics of Savonius wind turbines.

An application of cantilevered plates subjected to extremely large amplitude deformations: A self-starting mechanism for vertical axis wind turbines

The use of Darrieus straight-bladed vertical axis wind turbines (VAWTs) are becoming increasingly attractive for wind energy harvesting thanks to their distinctive advantages, even though these lift-force driven wind turbines suffer from anaemic self-starting capability, especially in areas with irregular wind regimes. In this paper, a novel self-starting mechanism is proposed for VAWTs. The proposed concept centres on the use of pliable plates in either of two distinct configurations: (i) with plates attached to the trailing edge of the rigid airfoil-shape blades of the VAWT; (ii) with plates installed inside the VAWT at a distance from the rotor. The feasibility of these designs for self-starting has been investigated theoretically. In particular, flexible blades are idealized as cantilevered beams placed at an angle to a uniform steady flow. Using a Hamiltonian framework, a geometrically-exact fluid-elastic continuum model is developed for the extremely large-amplitude deflections of the flexible blades. The fidelity of the developed framework is first validated against two sets of experimental data available in the literature. The developed framework is then used to estimate the static torque coefficients generated by the flexible plates in both aforementioned VAWT configurations. Finally, the self-starting efficacy of the proposed design is compared against a Savonius based mechanism used in a well-studied benchmark Darrieus–Savonius turbine. The numerical simulations reveal that, regardless of the initial static positions of the turbine, proper engineering of the pliable plates results in a torque generation capability which spins the turbine, even at low wind speeds. This finding proves the feasibility of the proposed concept as a potential self-starting mechanism for VAWTs. The advantages of this mechanism, such as easier design, manufacturing and implementation, enhanced reliability and economical maintenance, make this concept worthwhile for further exploration.

Design optimization of Double-Darrieus hybrid vertical axis wind turbine

This research emphasizes designing a straight-bladed Double-Darrieus hybrid vertical axis wind turbine (VAWT) with a high power coefficient as well as self-starting capability. Computational fluid dynamics analysis was performed using the sliding and dynamic meshing techniques. Various datasets were employed in the design of experiments to determine optimal configurations. A quadratic equation based on a regression model was established, and response surface methodology was applied to determine the accuracy of the model by analysis of variance, goodness of fit, investigation of residuals, and R-squared values. The optimized chord length, number of blades, pitch angle, distance of blades from the central rotating shaft, and rotor height were obtained as 0.547 m, 03, -3.41 deg, 0.789 m, and 1.605 m, respectively. A standard H-rotor Darrieus configuration, comprising symmetric airfoils and existing Darrieus-Savonius hybrid VAWTs were also analyzed for comparison. The positive static torque coefficient at all azimuth angles indicates that the proposed hybrid wind turbine is completely self-starting. The output power of the standard Darrieus configuration is substantially zero below a wind speed of 3.65 m/s, indicating that it is not capable of converting the kinetic energy of the airflow into electrical power below this specified value. On the contrary, the self-starting speed of the proposed hybrid wind turbine is as low as 2.81 m/s with a rated power of 1.522 kW at a wind speed of 7.5 m/s. The capability of the proposed hybrid wind turbine with a better power coefficient and transforming wind energy, even at low wind speeds, extends its utilization for various small to large-scale power projects. The proposed approach enables the determination of the optimum design configuration of a hybrid vertical axis wind turbine, along with a high-fidelity analysis in the early design phase.

Unjuk Kerja Performa Turbin Arus Laut Sumbu Vertikal Pada Berbagai Bentuk Sudu Unik

Efficiency and self-starting capability performances are the main problems in vertical axis turbines. By purposing improves its performance, vertical axis turbines have been developed with various models. One of the developments of this model is to design the turbine blades into unique shapes. This research aims to determine the performance of some unique blade vertical axis turbines conditioned on the same parameters, especially if applied in a marine environment. Turbines with helical blade (HB), eggbeater-shaped blade (ESB), diamond-shaped blade (DSB), Y-shaped blade (YSB), and arrow-shaped blade (ASB) were investigated based on efficiency and self-starting capability using QBlade software. Good performance symmetrical foils such as NACA 634021 are also applied to each turbine. The simulation results show that from the aspect of efficiency performance, turbine ASB > HB > ESB > DSB > YSB. Meanwhile, in the aspect of self-starting capability performance, the sequence is similar to efficiency performance, based on the two approaches applied. The highest efficiency achieved by the ASB turbine is 0.391 at the lowest tip speed ratio of λ = 4. The ASB turbine also achieves the best self-starting performance, which has a minimum static torque coefficient of 0.00155 and can produce the required power at the lowest marine current speed of 0.806 m/s. This performance brings the ASB turbine to produce a rated power of 52.52 kW, or more than twice the power production of the lowest efficiency turbine and has an average power gain of 3.75 kW per 0.2 m/s.