Wind Turbine Aerodynamics Research Articles

Numerical study on aerodynamics of small scale horizontal axis wind turbine with Weibull analysis.

This paper presents a computational fluid dynamics (CFD) analysis and blade element momentum (BEM) analysis of horizontal small-scale wind turbines under various parameters. Random airfoils such as the NACA 0012, NACA 0018, NACA 4412, S1016, S1210, S1223, and SC20402 are chosen, and the glide ratio is analysed. A Reynolds number of 100,000 is considered because of the small wind turbine design. The foil with the highest glide ratio is selected. Various notations are used to represent the chord and the twist angle of the blade, and the blade with the best chord and twist angle is chosen. The lift, drag, and power coefficients and power curves are analysed via the BEM. The power curves are evaluated for different air densities, and a higher value of power is obtained. Finally, via CFD, the SST model for turbulence is analysed for various angles of attack via Ansys Fluent for different air densities. The results are satisfactory compared with those of the CFD and BEM analyses. The Weibull distribution is analysed to understand the required frequencies for various wind speeds so that the installation of wind turbines can be made convenient in preferred areas with suitable wind properties.

A comprehensive numerical model for aero-hydro-mooring analysis of a floating offshore wind turbine

This paper presents a comprehensive study of a Floating Offshore Wind Turbine (FOWT), requiring multidisciplinary expertise in floating platform hydrodynamics, mooring system dynamics, and wind turbine aerodynamics. We introduce a fully coupled numerical model, focusing specifically on the NREL's (National Renewable Energy Laboratory's) 5 MW OC4 FOWT. The model is validated through both numerical simulations using the Computational Fluid Dynamics (CFD) based software OpenFOAM and experimental results. Key findings demonstrate the model's accuracy in forecasting the aerodynamic behaviors of the turbine, the platform's response to motions, and the behavior of the mooring system across diverse wind and sea state scenarios. Furthermore, the study enhances the understanding of FOWT's stability and efficiency by examining the influence of different Center of gravity (COG) heights. Results show that reduction in COG height has a minor effect on heave and surge motion but significantly decreases pitch motion and mooring line tension, thereby improving static stability and reducing the impact of wave loads on dynamic responses. Additionally, the results show that this reduction in COG height enhances the aerodynamic power output, suggesting that optimized FOWT designs could achieve improved energy capture efficiency. These insights optimize FOWT design and efficiency, enhancing renewable energy performance.

Comparison of aerodynamics of vertical-axis wind turbine with single and combine Darrieus and Savonius rotors

Vertical-axis wind turbines (VAWT) with Darrieus and Savonius rotors were studied based on the developed specialized package of computational aerodynamics. The flow structure around the Savonius and Darrieus rotors was numerically reconstructed, considering the mutual influence. From this reconstruction, the main stages of the vortex structure formation during the flow of the turbulent wind around the rotors were identified. Qualitative and quantitative assessments of the influence of the Savonius rotor on the total aerodynamic and energy characteristics of a VAWT were carried out. It is shown that the main contribution to the torque of the VAWT is due to the Darrieus rotor, mainly in the windward section of the trajectory. The Savonius rotor accounts for only a few percent of the total torque produced by the installation. The interaction of the Darrieus rotor blades with macrovortices from the Savonius rotor in the leeward part of the trajectory leads to a sharp drop in the torque coefficient. In the absence of a Savonius rotor, the vortices separated from supported tower are much smaller both in size and intensity. Therefore, their interaction with the blades of the Darrieus rotor does not lead to a significant change in the aerodynamic characteristics. A power characteristics comparison of two VAWTs showed that the torque coefficient is higher for wind turbines with only single Darrieus rotor. The developed approaches and techniques make it possible to reproduce real aerodynamic processes of flow most reliably around bodies of arbitrary shape and calculate their aerodynamic characteristics.

Investigation of wind turbine unsteady aerodynamics and trailing-edge noise characteristics under wake steering

In wake steering strategy, the shaft of an upstream wind turbine is yawed to deflect the wake and decrease the wake-swept area of the downstream wind turbine rotor. This intentional yaw misalignment increases the output power of the downstream wind turbine at the expense of some loss of upstream wind turbine power, consequently increasing the total wind farm power. However, the asymmetric non-uniform inflow into the downstream wind turbine due to the deflected wake causes unsteady aerodynamic loads and affects the wind turbine noise characteristics. In this study, the unsteady vortex lattice method coupled with the curled wake model is used to predict the unsteady aerodynamics of a downstream wind turbine in wake steering. Based on the unsteady aerodynamic results, the trailing-edge noise characteristics are predicted by a semi-empirical method. The impact of wake steering on trailing-edge noise level and amplitude modulation is evaluated. The results show that the asymmetric non-uniform inflow due to wake steering increases the amplitude modulation of the downstream wind turbine.

A novel vortex-based velocity sampling method for the actuator-line modeling of floating offshore wind turbines in windmill state

The fluid-dynamic simulation of wind turbine aerodynamics is typically tackled by applying multi-fidelity computational tools. In this context, the so-called actuator line model combines a low-fidelity treatment of the rotor with a high-fidelity resolution of the wake. In this paper, a novel formulation of the actuator line model proposes a vortex-based method to sample the flow around the rotor to rigorously assign the forces imparted by the blades. This new technique is implemented into an in-house code developed within the OpenFOAM environment, and it is validated against wind-tunnel experiments on a laboratory-scale horizontal-axis wind turbine operated in fixed-bottom and floating conditions. The calculations are also compared against multi-fidelity simulations performed, on the same test case, in the frame of the OC6 Phase III project. The simulation results, obtained after a systematic analysis and selection of the model parameters, exhibit a remarkable agreement with the available experiments and place the present code in the proper ranking of fidelity levels, in-between momentum-balance methods and blade-resolved CFD models. Finally, the calculations for surge and pitch platform motions demonstrate the capability of the proposed technique to reliably predict the aerodynamics of turbine rotors in dynamic operation at affordable computational cost.

Dragonfly-Inspired Blades for high Aerodynamic Performance small Horizontal Axis Wind Turbine

Inspired from the fascinating realm of Dragonfly features, this study intricately investigates the aerodynamic performance of a distinctive 1 m diameter small-scale Horizontal Axis Wind Turbine characterized by a unique bio-inspired tandem-blades configuration. Based on experimental wind tunnel tests and computational fluid dynamics simulations, the turbine performance is explored at different Tip Speed Ratios (TSRs). Remarkably, the bio-inspired turbine exhibits exceptional traits, achieving a notable peak power coefficient of approximately 0.35 at a low TSR of 3. A detailed investigation includes thorough analyses of pressure contours, relative velocity distributions, and individual blade contributions, revealing unique dynamics within the tandem configuration. The fore blade notably prevails in extracting wind energy, showcasing superior performance. While the hind blade influence in enhancing the fore blade efficiency emerges, underscoring the role of blade interactions in this bio-inspired designs. This study contributes significantly to the comprehension of the new design dragonfly-inspired wind turbine aerodynamics.

Validation of a Mid-Fidelity Numerical Approach for Wind Turbine Aerodynamics Characterization

This work is aimed at investigating the capabilities and limits of the mid-fidelity numerical solver DUST for the evaluation of wind turbines aerodynamic performance. In particular, this study was conducted by analysing the benchmarks NREL-5 MW and Phase VI wind turbines, widely investigated in the literature via experimental and numerical activities. The work was started by simulating a simpler configuration of the NREL-5 MW turbine to progressively integrate complexities such as shaft tilt, cone effects and yawed inflow conditions, offering a detailed portrayal of their collective impact on turbine performance. A particular focus was then given to the evaluation of aerodynamic responses from the tower and nacelle, as well as aerodynamic behavior in yawed inflow condition, crucial for optimizing farm layouts. In the second phase, the work was focused on the NREL Phase VI turbine due to the availability of experimental data on this benchmark case. A comparison of DUST simulation results with both experimental data and high-fidelity CFD tools shows the robustness and adaptability of this mid-fidelity solver for these applications, thus opening a new scenario for the use of such mid-fidelity tools for the preliminary design of novel wind turbine configurations or complex environments as wind farms, characterised by robust interactional aerodynamics.

Development and application of a mesh generator intended for unsteady vortex-lattice method simulations of wind turbines and wind farms

Abstract. In the last decades, the unsteady vortex-lattice method (UVLM) has gained a lot of acceptance to study large onshore–offshore wind turbines (WTs). Furthermore, and due to the development of more powerful computers, parallelization strategies, and algorithms like the fast multipole method, it is possible to use vortex-based methods to analyze and simulate wind farms (WFs). However, UVLM-based solvers require structured meshes, which are generally very tedious to build using classical mesh generators, such as those utilized in the context of finite element methods (FEMs). Wind farm meshing is further complicated by the large number of design parameters associated with the wind turbine (coning angle, tilt angle, blade shape, etc.), farm layout, modeling of the terrain topography (for onshore WFs), and modeling of the sea level surface (for offshore WFs), which makes the use of FEM-oriented meshing tools almost inapplicable. In the literature there is a total absence of meshing tools when it comes to building aerodynamic grids of WTs and WFs to be used along with UVLM-based solvers. Therefore, in this work, we present a detailed description of the geometric modeling and computational implementation of an interactive UVLM-oriented mesh generator, named UVLMeshGen, developed entirely in MATLAB® and easily adaptable to GNU OCTAVE, for wind turbines and onshore–offshore wind farms. The meshing tool developed here consists of (i) a geometric processor in charge of designing and discretizing an entire wind farm and (ii) an independent module in charge of computing the kinematics for the entire WF. The output data provided by the UVLMeshGen consist of nodal coordinates and connectivity arrays, making it especially attractive and useful to be used by other flow potential solvers using vortices, sources and sinks, or dipoles/doublets, among others. The work is completed by providing a series of aerodynamic results related to WTs and WFs to show the capabilities of the mesh generator, without going into detailed discussions of wind turbine aerodynamics, which are not the focus of this paper. The meshing tool developed here is freely available under a Creative Commons Attribution 4.0 International License (Roccia, 2023).

Advances and opportunities in wind energy harvesting using plasma actuators: a review

Abstract The dielectric barrier discharge plasma actuator has been recognized as a leading technology for controlling fluid flow and has found remarkable applications in wind energy harvesting over the past decade. Wind turbine aerodynamics are critical in this concept and performance is mainly determined by flow controllers, although significant technical progress is still required. This paper examines all the critical studies to investigate the potential application of plasma actuators for airflow control over wind turbines. This approach has been divided into three categories: wind turbine airfoils, horizontal-axis wind turbines and vertical-axis wind turbines aerodynamic performance and generated power. Finally, the potential functions of plasma actuators in current and future wind turbine generators are discussed. These actuators offer promising solutions to increasing power output, minimizing torque fluctuations and enabling self-starting capabilities, particularly in vertical-axis wind turbines. By adjusting blade pitch angles in conjunction with plasma actuators, significant improvements in airflow optimization and power extraction have been demonstrated. Despite the advancements, challenges persist, such as determining optimal actuator placement and overcoming structural limitations, especially concerning 3D effects and high Reynolds numbers. While plasma actuators enhance aerodynamic efficiency, their complexity needs to be balanced against marginal gains in power production, especially in high-megawatt turbines, for which controlling flow at low wind speeds is challenging. Future research must focus on the sustainable integration of plasma actuators, pitch angle adjustments and active control mechanisms to fully exploit the potential of wind energy for a sustainable future.

Moving actuator surfaces: a new concept for wind turbine aerodynamic analysis

The actuator disk is a concept often used in wind turbine aerodynamics, where the action of the turbine on the flow is averaged over time and space. This simplification stills retain sufficient physical information for wind turbine aerodynamic design. Its limitations are essentially related to the impossibility to model the blade shed vorticity. This paper presents a more general approach that uses rotating actuator surfaces carrying velocity and pressure discontinuities which are set from knowledge of the circulation around the model blade sections and using blade element analysis. The mathematics of rotating actuator surfaces, as well as an application to the TUDelft rotor are presented in this paper. The results are encouraging.

Optimizing NACA2414 airfoil aerodynamics with PARSEC parametrization and Genetic Algorithm

This research endeavours to contribute to the broader field of wind turbine aerodynamics by investigating a method to enhance the performance of airfoils, with specific attention to the NACA2414 airfoil at a 15-degree angle of attack. The study explores the airfoil’s performance across a range of -10 to 15 degrees angle of attack. It employs both PARSEC parametrization and Genetic Algorithm optimization, achieving significant advancements. At a 15-degree angle of attack, post-optimization, the lift coefficient for the NACA2414 airfoil exhibits a remarkable increase to 1.5275 at a Reynolds number of 105, surpassing the original airfoil’s performance of 1.2407. This progress highlights the effectiveness of utilizing PARSEC parametrization and Genetic Algorithm optimization, particularly in low-speed wind turbine applications. While emphasizing potential applications in low-wind-speed scenarios, the findings underscore the significance of these techniques in renewable energy production.

Wake characteristics of a balloon wind turbine and aerodynamic analysis of its balloon using a large eddy simulation and actuator disk model

Abstract. In the realm of novel technologies for generating electricity from renewable resources, an emerging category of wind energy converters called airborne wind energy systems (AWESs) has gained prominence. These pioneering systems employ tethered wings or aircraft that operate at higher atmospheric layers, enabling them to harness wind speeds surpassing conventional wind turbines' capabilities. The balloon wind turbine is one type of AWESs that utilizes the buoyancy effect to elevate the turbine to altitudes typically ranging from 400 to 1000 m. In this paper, the wake characteristics and aerodynamics of a balloon wind turbine were numerically investigated for different wind scenarios. Large eddy simulation, along with the actuator disk model, was employed to predict the wake behavior of the turbine. To improve the accuracy of the simulation results, a structured grid was generated and refined by using an algorithm to resolve about 80 % of the local turbulent kinetic energy in the wake. Results contributed to designing an optimized layout of wind farms and stability analysis of such systems. The capabilities of the hybrid large eddy simulation and actuator disk model (LES–ADM) when using the mesh generation algorithm were evaluated against the experimental data on a smaller wind turbine. The assessment revealed a good agreement between numerical and experimental results. While a weakened rotor wake was observed at the distance of 22.5 diameters downstream of the balloon turbine, the balloon wake disappeared at about 0.6 of that distance in all the wind scenarios. Vortices generated by the rotor and balloon started to merge at the tilt angle of 10∘, which intensified the turbulence intensity at 10 diameters downstream of the turbine for the wind speeds of 7 and 10 m s−1. By increasing the tilt angle, the lift force on the wings experienced a sharper increase with respect to that of the whole balloon, which signified a controlling system requirement for balancing such an extra lift force.

Numerical verification of the dynamic aerodynamic similarity criterion for wind tunnel experiments of floating offshore wind turbines

Model tests and real-time hybrid simulation tests of floating offshore wind turbines have recently been extensively conducted to explore the aero-hydro-servo-elastic coupling mechanism. The traditional thrust similarity criterion under the Froude scale cannot satisfy the dynamic aerodynamic similarity in the wave basin experiments. Meanwhile, the traditional model wind turbine in model tests shows huge differences in Reynolds number and significant deviations in the optimal tip speed ratio, and the dynamic performance is different from that of the prototype wind turbine. Therefore, a new criterion based on the mapping of the optimal tip speed ratio is proposed, and a new model wind turbine is designed to physically reproduce the dynamic aerodynamics of the prototype wind turbine accurately in wind tunnel experiments. Then the dynamic aerodynamic similarity in this criterion is numerically verified and compared with that in the traditional criterion. The simulation is performed in steady and unsteady inflows by the open-source OpenFAST. The platform motions of the prototype and model wind turbine are inflow-motivated and program-forced, respectively. The calculation results show that the dynamic thrust, power and their coefficients in the new criterion all maintain better similarity compared to those in the traditional criterion. This study is important for wind tunnel model tests and RTHS tests to accurately obtain unsteady aerodynamics, and it can guide the aero-hydro-structure load evaluations and turbine-floater-mooring integrated designs for large-scale floating offshore wind turbines.

Effects of non-isotropic blockage on a tidal turbine modeled with the Actuator-Line method

Blockage effects are a consequence of the interaction between a body and the surrounding boundaries in a constrained flow. For the case of tidal rotors, global blockage (β) is usually defined bythe ratio between the swept area of the rotor and the cross-sectional area of a channel. Increasingblockage tends to increase the limits of power extraction (Garrett and Cummins, 2007), as well asthrust on a rotor through an attendant increase of through-rotor mass flow. While these observations have been studied and demonstrated for isotropic blockage effects (e.g., Zilic de Arcos et al.2020, Bahaj 2007 , Mikkelsen 2002), questions remain regarding the validity of such assumptionsfor non-isotropic blockage in channels with, e.g., rectangular cross-sections with varying aspectratios.
 In this work, we will use CFD simulations to analyze the effect of non-isotropic blockage on atidal rotor. The study aims to explore these effects using an Actuator-Line representation of anaxial-flow rotor, simulated under different blockage ratios (1 %, 5 %, 10%, and 19.7 %), aspectratios (0.25, 0.5, 0.75, and 1), and tip speed ratios (4, 5, 6, and 7). A total of 64 cases will beconsidered. For each simulated case, the power, thrust, and spanwise force distributions will beextracted as functions of time, and used to understand the effect of blockage on the performanceof tidal rotors.
 Our preliminary results, in agreement with existing literature, indicate that blockage affectswake development, as seen in Figure , along with power and thrust. These results, for a constantaspect ratio, show power increases up to 26 % for a blockage of 20 %. The bulk of the simulationmatrix, including the different aspect ratios, is currently under production and is expected to beready before the paper submission deadline.
 
 ReferencesGarrett, C., Cummins, P. (2007). The efficiency of a turbine in a tidal channel. Journal of fluidmechanics, 588, 243-251.Zilic de Arcos, F., Tampier, G., Vogel, C. R. (2020). Numerical analysis of blockage correctionmethods for tidal turbines. Journal of Ocean Engineering and Marine Energy, 6, 183-197Bahaj, A. S., Molland, A. F., Chaplin, J. R., Batten, W. M. J. (2007). Power and thrust measurements of marine current turbines under various hydrodynamic flow conditions in a cavitationtunnel and a towing tank. Renewable energy, 32(3), 407-426.Mikkelsen, R., Sørensen, J. N. (2002). Modelling of wind turbine blockage. In 15th IEAsymposium on the aerodynamics of wind turbines, FOI Swedish Defence Research Agency.
 

Numerical investigation of rotational speed effects on flow separation and boundary layer dynamics in ducted wind turbines

In this paper, we conduct a comprehensive numerical investigation of a ducted wind turbine under various rotational speeds, focusing on aspects such as boundary layer thickness and momentum thickness. Our study utilizes advanced computational fluid dynamics techniques to assess the intricate flow characteristics and aerodynamics of the ducted wind turbine, providing a detailed understanding of its operation under different speed conditions. The primary objectives are to comprehend the effect of the wind turbine’s rotational speed on the boundary layer thickness and the momentum thickness, two crucial parameters influencing the turbine’s performance and efficiency. Our findings reveal a significant correlation between the increase in rotational speed and the growth of flow separation, a phenomenon typically indicated by an expansion in the area of negative wall shear stress. This research contributes valuable insights into the behavior of ducted wind turbines at varying rotational speeds, and the acquired knowledge could potentially be utilized in designing and improving wind turbine systems to achieve better performance and enhanced operational efficiency.

Performance analysis of low Reynolds number vertical axis wind turbines using low-fidelity and mid-fidelity methods and wind conditions in the city of Nottingham

The aerodynamics of small-scale Darrieus vertical axis wind turbines (VAWT) is investigated at chord-based Reynolds number between 1 ×105 and 1 ×106. Initially, wind resource assessment is done for two locations in Nottingham, UK for 4 years. Both locations experience highly unsteady wind and the average wind speed is lower for the location within the city than outside the city. Next, two analytical aerodynamic methods are compared: low-fidelity Double Multiple Streamtube and mid-fidelity Lifting Line Free Vortex Wake methods. Five 3D design parameters are investigated: number of blades, blade shape, chord length, blade height and blade pitch angle. Overall, the power coefficient values and trends agree well between the two methods. The differences arise either in cases of very low solidity or high solidity. The unsteady flow field is visualized for each case using instantaneous vortices and streamwise velocity contours in the wake. The aim of the current work is twofold. Firstly, to investigate the difference between the two methods based on the physical principles modeled by each method. The second aim is to have a better understanding of the VAWT flow physics by studying the complex 3D force and flow field, and fluid dynamic interactions in the VAWT wake.

Numerical Simulation Study on the Influence of Yaw-to-Wind Angular Velocity on Wind Turbine Aerodynamic Characteristics

In this paper, the wind turbine of NREL 5MW wind turbine is used as the research object, and the wind turbine is simulated from yaw-to-wind angle 30°-0° at different yaw angular velocities (0.5°/s, 1°/s, 2°/s) under rated operating conditions by using the slip grid model in fluent solver and custom UDF function program. The output characteristics and aerodynamic characteristics of the wind turbine under dynamic wind conditions are studied, and the effects of yaw angular velocity and yaw-to-wind angle on the output power, and near wake speed of the wind turbine are analyzed. The results show that the smaller the yaw angular velocity of the wind turbine is, the better the output power of the wind turbine can be obtained when the yaw angular velocity is 0.5 °/s 1 °/s 2 °/s. By analyzing the wake velocity, it is found that the smaller the yaw angular velocity is, the greater the larger the wake velocity loss area is.

Numerical investigation of h-Darrieus wind turbine aerodynamics at different tip speed ratios

PurposeThe purpose of the paper is to predict the aerodynamic performance of a complete scale model H-Darrieus vertical axis wind turbine (VAWT) with end plates at different operating conditions. This paper aims at understanding the flow physics around a model VAWT for three different tip speed ratios corresponding to three different flow regimes.Design/methodology/approachThis study achieves a first three-dimensional hybrid lattice Boltzmann method/very large eddy simulation (LBM-VLES) model for a complete scaled model VAWT with end plates and mast using the solver PowerFLOW. The power curve predicted from the numerical simulations is compared with the experimental data collected at Erlangen University. This study highlights the complexity of the turbulent flow features that are seen at three different operational regimes of the turbine using instantaneous flow structures, mean velocity, pressure iso-contours, blade loading and skin friction plots.FindingsThe power curve predicted using the LBM-VLES approach and setup provides a good overall match with the experimental power curve, with the peak and drop after the operational point being captured. Variable turbulent flow structures are seen over the azimuthal revolution that depends on the tip speed ratio (TSR). Significant dynamic stall structures are seen in the upwind phase and at the end of the downwind phase of rotation in the deep stall regime. Strong blade wake interactions and turbulent flow structures are seen inside the rotor at higher TSRs.Research limitations/implicationsThe computational cost and time for such high-fidelity simulations using the LBM-VLES remains expensive. Each simulation requires around a week using supercomputing facilities. Further studies need to be performed to improve analytical VAWT models using inputs/calibration from high fidelity simulation databases. As a future work, the impact of turbulent and nonuniform inflow conditions that are more representative of a typical urban environment also needs to be investigated.Practical implicationsThe LBM methodology is shown to be a reliable approach for VAWT power prediction. Dynamic stall and blade wake interactions reduce the aerodynamic performance of a VAWT. An ideal operation close to the peak of the power curve should be favored based on the local wind resource, as this point exhibits a smoother variation of forces improving operational performance. The 3D flow features also exhibit a significant wake asymmetry that could impact the optimal layout of VAWT clusters to increase their power density. The present work also highlights the importance of 3D simulations of the complete model including the support structures such as end plates and mast.Social implicationsAccurate predictions of power performance for Darrieus VAWTs could help in better siting of wind turbines thus improving return of investment and reducing levelized cost of energy. It could promote the development of onsite electricity generation, especially for industrial sites/urban areas and renew interest for VAWT wind farms.Originality/valueA first high-fidelity simulation of a complete VAWT with end plates and supporting structures has been performed using the LBM approach and compared with experimental data. The 3D flow physics has been analyzed at different operating regimes of the turbine. These physical insights and prediction capabilities of this approach could be useful for commercial VAWT manufacturers.

The Impact of Ice Formation on Vertical Axis Wind Turbine Performance and Aerodynamics

This study investigated the impact of ice formation on the performance and aerodynamics of a vertical axis wind turbine (VAWT). This is an area that is becoming more prevalent as VAWTs are installed alongside horizontal axis wind turbines (HAWTs) in high altitude areas with cold and wet climates where ice is likely to form. Computational fluid dynamics (CFD) simulations were performed on a VAWT without icing in Ansys to understand its performance before introducing ice shapes obtained through the LewInt ice accretion software and repeating simulations in Ansys. These simulations were verified by performing a wind tunnel experiment on a scale VAWT model with and without 3D printed ice shapes attached to the blades. The clean blade simulations found that wind speed had little impact on the performance, while reducing the blade scale severely reduced performance. The ice formation simulations found that increasing the icing time or liquid water content (LWC) led to increased ice thickness. Additionally, glaze ice and rime ice conditions were investigated, and it was found that rime ice conditions that occur in lower temperatures caused more ice to form. The simulations with the attached ice shapes found a maximum reduction in performance of 40%, and the experiments found that the ice shapes made the VAWT unable to produce power.

Investigations of aerodynamics of three-bladed combined type wind turbine

The field of renewable energy utilized is expanding. For this reason, many researchers in this field have centered on investigating the utilization of sustainable energy and diminishing the utilization of fossil fuels. The VAWTs is one of the sorts of wind turbines that are right now broadly utilized. Utilizing the Darrieus wind turbine, its beginning torque value is little due to the little projected area in contact with the wind stream. To extend this beginning torque, the vane-type blade with a vertical axis of revolution has been installed, which contains movable vans and installed with a three straight- bladed Darrieus airfoil (NACA0012) on the same turning shaft. In this paper, the characteristic of a combined three–blade vane type and three-bladed Darrieus turbine was talked about computationally by utilizing CFD (Fluent) software’ with k-ω turbulence model and commercial accessible solid work 2016. Through present study, the results gotten demonstrate that the beginning torque of the combined wind turbine increases when the blades with even movable vans are installed with the straight -bladed Darrieus wind turbine. Expanding the starting torque of the combined turbine because the wind stream is freely passed without any resistance through the movable vanes that are completely open on the inverse side of the wind direction, leads to an increment within the output power of the turbine compared to the comes about confirmed within the published sources of the vertical axis wind turbine, which has different shapes.