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Optimization of Magnus Wind Turbine Blades to Increase Operational Efficiency
Abstract
The problem of vortex disruption from the cylindrical blades of Magnus wind turbines is an urgent topic, which subsequently reduces the efficiency of the installation. Also, these cylindrical blades have a disadvantage in the form of low lift and high drag, as a result of which low operating efficiency is observed. Thus, the purpose of this work is a numerical study of the addition of a fixed blade to the cylindrical blades of a two-bladed wind turbine. Numerical studies were carried out for various angles of inclination of fixed blades from 0° to 60° using the Realizable k-ε turbulence model. The results of the study showed that with an increase in the angle of inclination of the fixed blade, the flow is disrupted, which is clearly visible at the maximum speed of rotation of the blades and the wind wheel, which causes a drop in lift, leading to a decrease in the efficiency of the wind turbine. Based on this, 0 degrees is the optimal angle of inclination of the fixed blade of a wind farm
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The need for energy and electricity has been increasing globally, and this means more power is required from the power plants. Power plants, however, will then continue harming the earth because of the greenhouse gasses produced while generating energies that contribute to global warming. Using renewable sources to produce clean energies is one of the sustainable methods to deal with such challenges. Wind energy is one of the renewable sources, which is accessible anywhere on earth, creating green energy. Wind turbines are mainly categorized into Horizontal Axis Wind Turbines (HAWT) and Vertical Axis Wind Turbines (VAWT). This paper firstly presents a general comparison between the HAWTs and VAWTs. Then, it presents mathematical modelling for the aerodynamic factors of HAWT and Darrieus VAWT to assist the researchers to understand some key design aspects of wind turbines, such as lift/drag ratio, tip speed ratio, power coefficient, and torque coefficient. Also, this paper presents a review of the aerodynamic performance of the recent VAWT designs to help researchers to identify and choose the best model among the Savonius and Darrieus rotors for further development or designing a new model at different wind conditions. This comparison review shows that for a large scale HAWT upwind 3 bladed wind turbines are the most optimum. The helical Savonius rotors perform better by having positive torque coefficient at all azimuth angles. Moreover, helical Darrieus was found to produce lesser noise and suitable for conventional areas. hybrid Savonius-Darrieus rotors can solve the self-starting challenge of the VAWTs, and they are suitable at low wind speeds. At last, this review shows some of the recent hybrid Savonius-Darrieus rotors which would help to solve the low efficiency of Savonius rotor and self-starting challenge of Darrieus rotors.
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This manuscript makes a significant contribution to the simulation modeling of innovative Wind Turbines based on the Magnus effect, which is becoming a promising technology in private houses. This research will assist the researchers to create correct mathematical modeling of the Magnus Wind Turbine for further realization control system based on maximum power tracking.
Abstract
Renewables have passed the peak of the inflated expectation hype cycle for emerging technologies, but interest in the design of new energy conversion devices is still high due to widespread distributed energy systems for private households. Magnus effect-based wind turbine combines mechanical and electronic engineering that provides a broader wind speed range and potential maximum power point tracking for deeper grid integration. This paper provides a comparative analysis of Magnus effect-based wind turbine simulation models and the development of the numerical model for the maximum power point tracking algorithm. The advanced model contributes to the reduction of the number of actual tests required for the mechatronics system tuning and deals with sustainability-related challenges, such as climate change and the development of new renewable sources of energy.
The article considers the influence of the relative roughness of a cylindrical blade on aerodynamic characteristics. It is known that the operation basis of blades under consideration is the Magnus effect, which is characterized by appearance of a lifting force (Magnus force), when the cylinders rotate in a transverse flow. This force is used to rotate the wind wheel, similar to lifting force, but can have a much larger value when selecting optimal conditions, both geometric and aerodynamic. The authors conducted a comparative analysis of cylinder layout with a relative roughness (0.005 ÷ 0.02). Experimental studies of aerodynamics process of rotating cylinders were carried out in the aerodynamic laboratory using the T-1-M wind tunnel at an air flow value of 5 to 15 m/s. Graphs of dependences of rotating cylinder's lifting force and drag force on the changing air flow velocity and on relative roughness, k/d, are obtained. For further study experimental cylinder layout’s aerodynamic parameters, the most optimal is the variant with a relative roughness value of 0.02, which had high indicators, was selected. In the course of experimental studies, graphs of the dependence of the values of lift and drag force on the angles of attack of a single rotating cylinder with a rough surface on the speed and angle of attack of the wind flow (0°, 30° and 60°) were obtained. It is established that the effective angle of attack is 0°, at which aerodynamic characteristics’s maximum values were obtained.
Splitter plates have been recognized as useful passive devices to reduce drag, mitigate flow-induced vibration, and enhance heat transfer efficiency of a circular cylinder. However, undesired torsional flow-induced vibrations due to splitter plate attachment require further investigation. This paper numerically studies the flow-induced torsional vibrations of an elastically mounted circular cylinder with an attached splitter plate in laminar flow with a Reynolds number of 100. A finite volume formulation is utilized to solve the incompressible two-dimensional fluid governing equations. Torsional vortex-induced vibrations (VIVs) are observed at lower reduced flow velocities, while a symmetry-breaking bifurcation occurs as the reduced flow velocity increases, after which the cylinder-plate assembly vibrates around a nonzero equilibrium angle. The numerical results show that the synchronization range of VIV extends, the peak VIV amplitude increases, and the critical reduced flow velocity for the bifurcation decreases with decreasing the moment of inertia. The symmetry-breaking bifurcation is due to a combined effect of the structural restoring moment and the flow-induced moment. The critical reduced velocity of the bifurcation and the nonzero equilibrium angle at any reduced velocity can be calculated based on the mean moment coefficients of the cylinder-plate assembly. The flow-induced moment is mainly induced by the pressure difference between the splitter plate's upper and lower surfaces. The phase difference between the torsional moment and displacement is 0° at lower reduced velocities, while the phase difference jumps to 180° at a reduced velocity of approximately 6.5. The mean drag coefficient of the vibrating cylinder-plate assembly is lower than the mean drag coefficient of a stationary circular cylinder but often higher than that of a stationary cylinder-plate assembly. The dominant frequency of the drag force is twice the vibration frequency before the symmetry-breaking bifurcation, while the dominant frequency becomes consistent with the vibration frequency after the bifurcation. The typical 2S mode of vortex shedding is identified for all considered moments of inertia and reduced flow velocities. However, the timing of a non-shedding vortex changes at the critical flow velocities for the phase jump and symmetry-breaking bifurcation. The observed torsional vibrations suggest that circular cylinders with splitter plate attachments may be competitive candidates for VIV-based energy harvesting, while they may not be good choices for heat exchangers.
A novel approach for the modeling of rotor‐integrated aerodynamic loads is suggested to answer the need for a comprehensive, insightful, and analytical actuator disc model. All the six degrees of freedom (including tangential components) are considered. It is shown that loads may be written as a quadratic form of a reduced six‐component velocity vector at the hub. The individual contributions of lift and drag, azimuthal variations, as well as blade pitching and tip losses are isolated. Errors introduced by the necessary approximations are discussed, and parametric corrections are considered. Parameter identification methods are then suggested, and the performance of the resulting calibrated analytical models is assessed. Results show that the new modeling approach is able to accurately model both the mean values of the thrust and power coefficients and their derivatives with respect to tip‐speed ratio and pitch angle across the full range of operating wind speeds. Furthermore, it is able to reconstruct the general rotor behavior with a minimal amount of information available. Tangential components are also well modeled, although they require the knowledge of airfoil properties. The model's architecture leaves room for extensions to dynamic flow, skewed flow, and azimuthal load variations.
Understanding the interaction of vortical gusts and unsteady wing kinematics is crucial to the operation of small aircraft in urban or turbulent environments. Studies investigating this interaction require adequate control of a vortical gust generator to consistently produce the desired vortical gusts for study. Previous studies have focused on the pitching or heaving of airfoils to generate vortical gusts. The current study focuses on the characterization of the vortex shedding process for a rotationally oscillating circular cylinder with an attached one-diameter long plate. When this vortical gust generator is actuated in relatively small sinusoidal motions, von Kármán vortices can be generated in a controllable and repeatable fashion over a large range of oscillation frequencies that are significantly different than the natural shedding frequency of the static cylinder, and without the generation of any additional unwanted vorticity. Fine tuning of the actuation parameters allows for the control of the vortex strength, frequency, and transverse location.
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Wind energy, together with other renewable energy sources, are expected to grow substantially in the coming decades and play a key role in mitigating climate change and achieving energy sustainability. One of the main challenges in optimizing the design, operation, control, and grid integration of wind farms is the prediction of their performance, owing to the complex multiscale two-way interactions between wind farms and the turbulent atmospheric boundary layer (ABL). From a fluid mechanical perspective, these interactions are complicated by the high Reynolds number of the ABL flow, its inherent unsteadiness due to the diurnal cycle and synoptic-forcing variability, the ubiquitous nature of thermal effects, and the heterogeneity of the terrain. Particularly important is the effect of ABL turbulence on wind-turbine wake flows and their superposition, as they are responsible for considerable turbine power losses and fatigue loads in wind farms. These flow interactions affect, in turn, the structure of the ABL and the turbulent fluxes of momentum and scalars. This review summarizes recent experimental, computational, and theoretical research efforts that have contributed to improving our understanding and ability to predict the interactions of ABL flow with wind turbines and wind farms.
Magnus force shows extraordinary results in producing lift force, hence gives rise to its application. One of the applications is by replacing airfoil-shaped blades of wind turbine with the rotating cylinder blades. This is known as Magnus Wind Turbine (MWT), where it generates lift force on the rotating cylinder that perpendicular to the incoming wind flows. Due to high consumption of fossil fuel, natural gas and coal that risk our and earth health. Thus to overcome this conundrum, MWT is one of the innovative approaches to harvest the low wind speed energy. This paper presents an overview of the horizontal-axis MWT state-of-the-art.
The Magnus wind turbine is an invention that uses rotating cylinders as blades to extract energy from the wind. This invention overcomes the limitation of operating a wind turbine at low wind speed conditions. However, research regarding the torque generated by enhancing the surface roughness of the Magnus wind turbine is still lacking. Thus, the study aims to understand the effect of varied sandpaper surface roughnesses on the Magnus wind turbine torque output. The approaches used are: experimentation using a 6 cylinders model inside a wind tunnel for Magnus force comparison, a Magnus wind turbine model for torque performance and smoke flow visualisation for boundary layer analysis. The results show that the torque coefficient produced by P40 sandpaper to smooth the surface roughness is 0.079–0.016, which is nearly a five times improvement in the torque coefficient. On the other hand, the tip speed ratio further increases from smooth to rough surface enhancement (0.057–0.147). This significant finding indicates that the Magnus wind turbine performance can be further improved using sandpaper surface roughness.
Many efforts have been dedicated to examining the flow characteristics around a pair of cylinders. Despite the straightforward geometry, the flow dynamics around a cylinder prove to be intricate. The practical applications of this phenomenon extend across various engineering domains, including oil and gas transmission lines, heat exchangers, pipelines, and the construction of successive skyscrapers. The current investigation delves into the examination of the critical distance ratio, fluctuating velocity, flow pattern, and drag surrounding two sequential circular and square cylinders. The governing equations are solved using the finite volume method (FVM). For momentum, turbulent kinetic energy, and turbulent dissipation rate equations, the upwind second-order discretization is used. The findings, acquired at a Reynolds number of 32,000 for distance ratios ranging from 0.25 to 10, are then compared with those from single-cylinder cases. The results highlight the significant influence of both geometry and the distance between cylinders on the observed flow patterns. The critical distance ratio is obtained as
= 2 and 2.5 for the case of two sequential circular and square cylinders, respectively, while for the case of combined circular and square cylinders, it is calculated as
= 3. The non-dimensional fluctuating velocity decreases by 7%, 26%, and 38% in the case of two sequential circular cylinders with distance ratios of S* = 1, 2, and 3 at the first station, respectively, compared to a single circular cylinder. The drag coefficient is 50% lower in the two sequential circular and square cylinders case compared to the single square cylinder.
Wind energy is a clean and fast-growing renewable energy source that can be harnessed using wind turbines. In a Vertical Axis Wind Turbine (VAWT), turbine blades are a crucial factor, and their fiasco leads to wind turbine failure. However, references to VAWT blade structural analysis are very limited. Therefore, the study was carried out to determine the material with the lowest degree of deformation without structural failure. The finding could be used as a recommendation in the material selection of Savonius type vertical axis wind turbine blades. The study used materials such as aluminum, stainless steel, and fiberglass. The analysis was carried out by simulating using ANSYS software. Computational Fluid Dynamics (CFD) was used for determining the loading by providing speed variations at 3 m/s, 4 m/s, 5 m/s, and 6 m/s. The Finite Element Analysis (FEA) method was applied to analyze the structure, which shows the results of total deformation, equivalent stress, and safety factor. The total deformation results from the aluminum blades showed values of 109.55 mm, 190.73 mm, 299.25 mm, and 425.39 mm. The safety factor values of 4.4049, 2.5166, 1.5647, and 1.1348 revealed that it was also technically safe. Aluminum material can be recommended to be used in the manufacture of Savonius type vertical axis wind turbine blades because of its low price, lightweight, corrosion resistance, and sufficient durability, as revealed from the results of total deformation and safety factor values.
The results of a numerical study of the flow around a circular rotating cylinder under the subcritical regime of the Reynolds number are presented. A numerical flow simulation was carried out using the Realisable k-ε turbulence model, which effectively visualizes the fallout of vortices. At Reynolds numbers 16,000, 30000, and 50,000 and revolutions 300,500 and 700, the velocity field around the cylinder with the plate and the static pressure distribution field around the cylinder with the plate are obtained. It is determined that with an increase in the rotation frequency of the cylinder with the plate, the vortex formation increases. In the future, there will be an increase in lifting force and drag force due to an increase in flow velocity and, consequently, a decrease in pressure. Due to the rotational motion, there is a change in the pressure field at the ends of the cylinder with the plate.
The vortex shedding is one of the main reasons for vibration in cylindrical bodies. Accordingly, by controlling the vortex shedding, the vortex-induced vibration (VIV) can be controlled in these objects. Correcting the shape of objects through installing trip wires, installing screw plates, and creating holes on the object can reduce these vibrations. For this purpose, in the present study, the effects of installing four trip wires with different diameters on the vortex pattern, mean and fluctuation velocities, characteristics of the wake such as defect velocity and half width are numerically investigated in variable stations (X/D = 1.06, 1.54, 2.02, 5, 7, 10) at different inlet velocities 2.85, 10 and 20 m/s. The diameter of the circular cylinder was 20 mm, and the diameter of the installed trip wires was 0.25, 0.5, 0.75, 1, and 1.5 mm. The disturbance trip wires were installed at positions θ = ± 40 and ± 140. The results showed that the vortex pattern is sensitive to the installation of trip wires. By decreasing the diameter of the trip wires, the length of the shear layer decreases. In the area near the model (rotating area), the half width increases for a smooth cylinder. The velocity defect parameter is decreased by increasing the Reynolds number and decreasing the diameter of the trip wires.
Recent studies found that tubercles had been integrated into various applications beyond nature to enhance performance. Therefore, the present work investigates the performance of a Savonius turbine with various tubercle configurations at a wind speed of 7 m/s which corresponds to a Reynolds number of 148,000. The Savonius turbines with tubercle features were initially designed and inspired by the distribution of tubercles on the flippers of humpback whales. However, only the models with the best performance were chosen for fabrication and tested in the wind tunnel. The new turbine designs have 33% of the blade without tubercles, with turbine model 1 (D1) having a large tubercle beginning in the midspan and tapering towards the endplates, while turbine model 2 (D3) applies the 33% without tubercles in the midspan of the blade. The results demonstrated that turbine model 1 had the highest maximum Cp of 0.19 at the tip speed ratio of 0.78 and indicated that the spanwise location of tubercles in which it is integrated into the turbine is a significant geometric arrangement to improve the performance. The new turbine models designed with tubercles performed significantly better than the baseline model, with 46.15% and 23.08% improvements, respectively. The flow visualization for both models with tubercle configurations showed smaller wake sizes that represent reduced drag and eventually produced higher performance in comparison with the baseline. The results provide insights into the implementation of the tubercles concept on a Savonius turbine with a low aspect ratio.
In this paper, the flow past a freely rotating cylinder-plate body is numerically investigated within a laminar flow region. The effects of Reynolds number and plate length on the rotary oscillation, wake flow, and hydrodynamic characteristics are examined. Numerical results indicated that the bifurcation phenomenon, i.e., the equilibrium position of the rotary oscillation deflects to a position which is not parallel to the free stream, is found in most cases. According to the variations of equilibrium position and root-mean-squared rotary angle (the root-mean-squared value of rotary oscillation obtained from sufficient stable rotary periods) against Reynolds number, three different rotation modes are identified: non-bifurcation regime without rotary oscillations (mode I), bifurcation regime with tiny rotary oscillations (mode II), and bifurcation regime with large rotary oscillations (mode III). Both the equilibrium position and root-mean-squared rotary angle increase first and then converge to a nearly unchanged value as Reynolds number increases. The splitter plate length has significant impacts on rotary oscillation responses. Generally, the cylinder with longer splitter plates possesses smaller deflection but larger root-mean-squared rotary angle. Moreover, a longer plate will push downstream the shear layer interaction, leading to a longer recirculation region and thus a smaller lift force. Due to the deflection, the upper and lower separation points of the rotatable cylinder-plate body are not symmetrical. The 2S vortex shedding pattern is recognized when the structure rotates, where two vortices are shed from the tip and the lower side of the plate, respectively. Additionally, three different reattachment behaviors are identified according to the position of the reattachment points: symmetrical reattachment (SR), asymmetrical tip-reattachment (ATR), and asymmetrical side-reattachment behavior (ASR). As compared with a bare cylinder, the rotatable splitter plate is helpful to reduce the drag and lift forces and meanwhile suppress vortex shedding.
This study experimentally investigated the effects of the helical strakes on the characteristics of the wake around the circular cylinder at Reynolds numbers of 10,000 and 40,000. In proportion to the diameter of the investigated model, the heights of the investigated strakes were 1.5 and 2.1 mm, which were equal to H/D = 0.05 and 0.07, respectively. On the above-mentioned model, there were 3 strakes with equal installation intervals, whose pitches were equal to 3D. The effect of changes in the height of the helical strakes and Reynolds number on the characteristics of the wake in the centerline of the cylinder wake were measured and explored. Moreover, using the measured values, the parameter of velocity defect, half of the wake width at half depth, and Strouhal numbers were calculated. The results revealed that increasing the height of the helical strakes at constant Reynolds number decreases the turbulence intensity in the wake. Furthermore, helical strakes reduces the value of the critical Reynolds number. To investigate the fluid forces applied to the model, the value of the drag coefficient was also calculated. The results indicated that using helical strakes generally reduces the drag coefficient of the cylinder.
The paper numerically investigated the flow past a circular cylinder with a detached splitter plate at a low Reynolds number of 100. This cylinder-plate body could freely rotate around the cylinder center as a whole. The examined gap ratio G/D between the rear base of cylinder and the leading edge of plate increases from 0 to 2. Numerical results illustrate the occurrence of the bifurcation of flow-induced rotation at 0 ≤ G/D ≤ 0.5 while it disappears at 0.55 ≤ G/D ≤ 2. In the bifurcation regime, the time-averaged offset angle (θmean) decreases monotonically with increasing G/D. However, the bifurcation suddenly disappears as θmean drops from 9.64° at G/D = 0.5 to 0° at G/D = 0.55. The root-mean-squared rotation angle θrms increases approximately linearly at 0 ≤ G/D ≤ 1.6, and then jumps to a high value around 4.69° at G/D = 1.7 and approximately remains the value as G/D further increases. The typical 2S (two single vortices alternately shed per cycle) shedding mode is observed in the wake. Nevertheless, four interaction behaviors are identified according to the position of vortices with respect to the splitter plate, including the bilateral, totally wrapped, partially wrapped and unilateral interaction patterns. The variation of hydrodynamic forces for the individual plate is similar to the whole cylinder-plate body, indicating the main contribution from the plate. Compared with the bare circular cylinder, distinct drag- and lift-reductions are achieved at G/D = 0.1–1.6 and 0–1.6, respectively. The maximum reduced percentages of drag and lift forces for the circular cylinder reach 12.04% and 82.35%, respectively.
In order to study the impact of the wind speed and turbulence model on the numerical simulation of the aerodynamic characteristics for the wind turbine, SST k–ω and transition SST turbulence models were used to numerically simulate the aerodynamic characteristics at 7 m/s, 10 m/s and 20 m/s inlet wind speed, and the numerical results were compared with the experimental results. The results show that as the low inlet wind speed, no flow separation occurs over most of the blade surface, and SST k–ω and transition SST turbulence models can accurately predict the aerodynamic characteristics of the blades. As the low inlet wind speed, the flow separation mainly occurs around the root and the middle of blade, and numerical results at the leading edge by SST k-ω turbulence model and near the trailing edge by transition SST turbulence model match the experimental results well. When most of the flow through the blade surface is completely separated, the numerical simulation results by both SST k–ω and transition SST turbulence models have certain differences with experiment results, and the deviations are mainly concentrated on the suction surface and decrease gradually from the blade root to the tip.
This work aims to investigate computationally the performance of Savonius vertical axis wind turbine having a new design feature for its blade geometry. The proposed design is based on a universal consideration of blade shape factor concept for the Savonius rotor blade. A blade shape factor ranges from zero to infinity, or vice versa, is considered in a single blade of the modified Savonius rotor. This means that each point in the two-dimensional blade profile of the suggested blade design has a single value of blade shape factor that is defined based on the dimensions of conventional semi-circular blade. The computational results of the proposed blade shape design, having blade shape factor varying from infinity to zero, showed an improvement in turbine performance as compared to conventional blade shape design. Moreover, increasing the operating range of Savonius wind turbine is expected.
The behavior and characteristics of the wake produced behind an elliptic cylinder at 0° angle of attack, in the presence of trip wires, are investigated experimentally and numerically. For this purpose, an aluminum cylinder model with an elliptic cross section and a length of 390 mm, major diameter of 42.4 mm and minor diameter of 21.2 mm was tested in the test section of a wind tunnel. Realizable k–ε turbulence model was used for the numerical analysis and SIMPLEC algorithm was employed for pressure–velocity coupling. Reynolds numbers corresponding to the major diameter of the cylinder were 38,550 and 64,250 for air velocities of 15 m/s and 25 m/s, respectively. Turbulence trip wires of .5 mm diameter were installed symmetrically on the elliptic cylinder at angles of 23.7° and 40.9° relative to the stagnation point. The drag coefficient for the smooth elliptic cylinder was about .6 at both Reynolds numbers. Results showed a drag coefficient reduction of 75% in the best possible case. It was also concluded that a turbulence promoter wire has a significant effect on flow characteristics and reduction in the drag coefficient, and that it strongly depends on the location where the trip wire is installed on the model.
Wind energy is one of the renewable energy with no pollution and low-cost. Many countries especially those with high wind speed have been widely applying wind turbine in generating electricity and managed to reduce much cost of power generation. As the wind turbine relies on the wind, the use of large wind turbine in countries with low wind speed is impractical for the fact that wind is insufficient and not afford to rotate the wind turbine. Thus, small size wind turbines are more appropriate under low speed wind condition. However, small wind turbine suffers from high vortex downstream to the wind turbine that leads to high power losses. Reliable and practical wind turbine in countries whose wind speed is low is the idea behind the work done in this research. The effect of vortex formation on the performance of the downstream small wind turbine is investigated using numerical approach. A suitable modelling and simulation method are identified for the purpose of wake simulations behind a single wind turbine and the important data with respect to the effect of different spacing between wind turbines are also studied.
Magnus rotor is essentially a rotating cylinder that
generates lift due to Magnus effect. The effect has been
generating curiosity in a wide variety of fields ranging from
sports to alternate energy. The wind turbine under
investigation replaces tradition blades that have an airfoil
cross-section, with such Magnus rotors. In this paper, Magnus
wind turbines with three and five rotors have been analyzed at
various velocity ratios and tip speed ratios. The primary
motive is to find the best operating conditions for obtaining a
higher lift to drag coefficient for both three and five rotor
turbines, so that it can generate more power with the least
available wind. It has been observed that the higher ratio of
coefficient of lift to coefficient of drag values were obtained for
lower values of tip speed ratio, which is in contrast to the
requirement of higher tip speed ratios for turbines with airfoil
cross-section. This translates to the fact that Magnus wind
turbines can be an efficient solution to the generation of wind
power with less noise generation, since the noise generated by a
wind turbine decreases with decrease in the tip speed ratio.
Similar to other distributed generation sources, wind turbines cause power quality disturbances (PQDs) issues in power systems. One of the most important PQDs that has bad effects on sensitive loads is flicker. In this study, an algorithm is presented for assessment and recognition of different factors causing flicker of wind turbines. Some aerodynamic factors (wind shear and tower shadow) and some mechanical factors (blade pitching errors, gearbox tooth crash and turbine blade break down) are modelled using fixed speed wind turbines. Then, wavelet transform and S-transform are used to extract some dominant features voltage. Then, in order to avoid large dimension of feature vector, Relieff feature selection method is applied to extracted features. The probabilistic neural network (PNN) is used to classify above-mentioned factors. The only adjusted parameter of the PNN classifier is determined by using the particle swarm optimisation technique. Moreover, the short-term severity of flicker (Pst) is calculated for each type of fault as extra features to increase the severability of extracted features. Results show that the classifier can detect different causes of flicker event with high detection accuracy.
Numerical investigation of vortex formation effect on horizontal axis wind turbine performance in low wind speed condition
- Nurul Majuni
- Izyan
- M Fazila
- Zawawi
Nurgul Nayzabekovna Shuyushbayeva and Ainura Nurtaevna Dyusembaeva
- Asem Bakhtybekova
- Ravshanbekovna
- Nazgul'kadyralievna
- Leonid Leonidovich Tanasheva
- Minkov
Bakhtybekova, Asem Ravshanbekovna, Nazgul'Kadyralievna Tanasheva, Leonid Leonidovich Minkov, Nurgul
Nayzabekovna Shuyushbayeva and Ainura Nurtaevna Dyusembaeva. "Aerodynamic features of a rotating cylinder
with a deflector." Journal of Applied Mechanics and Technical Physics 63, no. 5 (2022): 833-842.
https://doi.org/10.1134/S0021894422050121
The investigation of the effect of the helical strakes' height on the cylindrical wake
- A Bak Khoshnevis
- M Boloki
- M Yadegari
Bak Khoshnevis, A., M. Boloki and M. Yadegari. "The investigation of the effect of the helical strakes' height on the
cylindrical wake." Journal of Solid and Fluid Mechanics 10, no. 1 (2020): 223-236.
Savonius-Magnus Hybrid Turbine Design Performance Based on Computational Fluid Dynamics
- Rr Hendaryati
- Heni
Hendaryati, Rr Heni, Achmad Fauzan Hery Soegiharto, Dolly Salwansyah andinusa Rahmandika and Bahrul Jalaali.
"Savonius-Magnus Hybrid Turbine Design Performance Based on Computational Fluid Dynamics." CFD Letters 16,
no. 10 (2024): 43-53. https://doi.org/10.37934/cfdl.16.10.4353
CSS-Center for Sustainable Systems
- University Of Michigan
University of Michigan. "CSS-Center for Sustainable Systems." University of Michigan. https://css.umich.edu