A New Super-Productive VAWT

Large fixed and floating wind farms are planned in the US, the first of which will come on stream along the East Coast, and then possibly followed by the West Coast in deepwater. However, there are other regions in North and South America, and even the Caribbean that are rapidly aiming for offshore wind farms. One of those locations, offshore Texas, may develop ahead of the West Coast by taking advantage of the unparalleled expertise in ocean engineering in Texas gained through over 40 years of offshore oil and gas developments. In addition, Texas has regional competitive advantages that could result in another offshore boom for the region. Texas is the leading state for onshore wind power and consequently has some highly innovative research institutions and initiatives that could further push Texas to the forefront of regional, if not global, offshore wind technology development and deployment. The additional advantages that Texas can provide to wind farm developers based on its proximity to the Caribbean and South American offshore wind markets are also presented. As an example of innovation in Texas, the University of Texas at Dallas, DOE ARPA-E (Department of Energy Advanced Research Projects Agency – Energy) funded vertical axis wind turbine (VAWT) development is summarized (ARPA-E, 2020). While elements of VAWT technology are transferable to horizontal axis wind turbine (HAWT) technology to improve HAWT performance, more generally, the deployment of VAWTs overcomes many logistical and performance problems inherent in deploying HAWTs offshore. Such VAWT advantages are discussed. Two cases are presented comparing HAWT versus VAWT floating wind farms. The technology and execution differences of the two cases are compared and the net present value and internal rate of return are calculated conserving the technology differences. Discussion of forthcoming additional financing opportunities is also presented to illustrate how even in low-cost electric rate markets, offshore wind can still be feasible.

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.

Double-blade vertical axis wind turbines (DB-VAWTs) can improve the self-starting performance of lift-driven VAWTs. We here propose the quadruple-multiple streamtube model (QMS), based on the blade element momentum (BEM) theory, for simulating DB-VAWT performance. Model validity is investigated by comparison to computational fluid dynamics (CFD) prediction for two kinds of two-dimensional DB-VAWT rotors for two rotor scales with three inner-outer radius ratios: 0.25, 0.5, and 0.75. The BEM-QMS model does not consider the effects of an inner rotor on the flow speed in the upwind half of the rotor, so we introduce a correction factor for this flow speed. The maximum power coefficient predicted by the modified BEM-QMS model for a DB-VAWT is thus closer to the CFD prediction.

Enhancing vertical axis wind turbine by dynamic stall control using synthetic jets

In this study, performance of different wind turbines is compared with using QBlade software. Normally wind turbines are categorized as Horizontal Axis Wind Turbine (HAWT) and Vertical axis wind turbine (VAWT) which in this paper Darrieus type as a VAWT is discussed with HAWT. The airfoil selected for this study is NACA 0012 and from simulations it can be resulted how adding blades influence efficiency in wind turbines. In terms of using wind turbines, number of blades is one of the important parameters. QBlade contains the XFOIL airfoil analysis functionalities which makes a software a single tool that comprises all functionality needed for the design and simulation of vertical and horizontal axis wind turbines. The benefits of the proper airfoil design optimal is increasing the efficiency of wind turbines and maximization of the power produced.

The vertical axis wind turbine (VAWT) is considered an important device to utilize the renewable and sustainable wind energy. However, the relatively lower power coefficient has hampered its development. Therefore, this paper attempts to investigate the effect of swept blade employed in a VAWT on the enhancement in aerodynamic performance. A series of swept blades were studied in a small VAWT rotor, and the RANS SST k-ω turbulence model was utilized to simulate the flow field. The numerical model was validated against experimental data, and the aerodynamic performance was investigated with respect to force coefficients, vorticity distribution, static pressure distribution, and wind turbine wake, respectively. The results indicated that the swept blade could effectively increase power outputs by about 20% for the wind turbine. By reducing the drag coefficient, a high lift-drag ratio was achieved. And this configuration prevented the blade from suffering severe dynamic stall. Besides, the swept blade changed the distribution of low wind speed area in the wind turbine wake, which should be considered in the wind farm. It was concluded that this work provided a new way for the practical design and optimization of wind turbine.

This Vertical-axis wind turbines (VAWTs) are emerging as promising alternatives to conventional horizontal-axis wind turbines (HAWTs) for renewable energy generation, particularly in urban and offshore environments. Despite increasing interest, a comprehensive evaluation of their technical, economic, and environmental performance remains limited. This review, based on a targeted literature search, critically evaluates and compares the performance, economic viability, environmental impact, technological advancements, and adoption barriers of VAWTs and HAWTs. VAWTs demonstrate lower aerodynamic efficiency (20–35%) and capacity factors (20–35%) compared to HAWTs (efficiency 40–50%, capacity factors 30–45%), yet offer advantages such as omnidirectional wind capture, simpler ground-level maintenance, lower noise emissions, reduced avian impact, and greater feasibility for space-constrained urban settings. Economic analyses indicate that VAWTs typically have higher levelized costs of energy (60–80 EUR/MWh) than HAWTs (40–60 EUR/MWh), although these are partially offset by reduced operational costs. Environmental assessments favor VAWTs in terms of land use, biodiversity impact, and water consumption. Technological progress, including AI-based aerodynamic optimization, hybrid rotor designs, advanced composite materials, and Maglev bearings, has enhanced the competitiveness of VAWTs. The main adoption challenges are lower power output, scalability constraints, and lack of support from policymakers. While HAWTs remain dominant in large-scale wind energy production due to superior aerodynamic performance and economies of scale, VAWTs offer significant benefits for decentralized, urban, and offshore applications where installation flexibility, noise, and environmental considerations are critical. Continued innovation and more policy support could increase VAWT market penetration and contribute to more diversified, sustainable energy portfolios.

In South East Asia countries such Malaysia, wind turbine is generally not suitable to be used in large scale to generate electricity due to inconsistent wind speed and suitable land site availability. However, a small scale application is of preference as the wind speed in the region lies within the low speed range of approximately 2-5 ms−1 with intermittent highs up to 8 ms−1. The performance of Vertical Axis Wind Turbines (VAWTs) is known to be better compared to Horizontal Axis Wind Turbines (HAWTs) in urban conditions due to its omnidirectionality, which allows it to operate in fluctuating turbulent wind conditions. However, the major drawback of VAWTs is the inability to self-start under low wind speed conditions. Hence, the objective of this work is to investigate the Pivoting Panel Mechanism (PPM) which aims to assist VAWT models to self-start at low wind speed condition. Three sets of PPM width configurations (70mm, 80mm, 90mm) are used to study the effect of increasing the pivot panel surface area on the VAWT performance. Performance test showed that the PPM model improved the power coefficient values at the tip wind speed range of TSR<0.75 (PPM 70mm>80mm>90mm). Further investigation revealed that the larger PPM surface area (90mm) was able to assist the VAWT model to achieve a shorter RPM response time at wind speed of v = 2.5ms−1 and 2.9ms−1. These findings have considerable implications for future researches for the optimization of PPM design parameters and its adaptations in VAWT turbine design.

The Design and Flow Simulation of a Power-augmented Shroud for Urban Wind Turbine System

In this paper, the reason was analyzed that the aerodynamic efficiency of the traditional vertical axis wind turbine (VAWT) was always low, and a new type of VAWT—Guiding VAWT was introduced. On that basis, a new blade shape called as combined blade for Guiding VAWT was proposed and numerical investigation was complemented on its aerodynamic performance by CFD (Computational Fluid Dynamics) technique. This Guiding VAWT includes two components: guiding impeller and rotating impeller, which are both combined blade in shape. The guiding blade is combined by three sections: inlet radial section, middle arc section and outlet linear section. The wind blade is combined by two sections, inlet arc section and outlet linear section. The combined guiding blade may not only avoid the wind impeller from the direct impact by the coming flow on its convex surface of the blade so as to decrease the drag torque but also improve the effective impact by the coming flow on the concave surface of the blade, both of which contribute the enhancement for the driving torque of the wind turbine. Results indicate: This new type of Guiding VAWT with combined blade has a wider operating range, higher aerodynamic efficiency than the traditional VAWTs. And more, this paper introduced the airfoil blade into this new type of VAWT and numerically validated that even though the flow inside VAWT was a large separated flow with variable attack angles, the aerodynamic advantage of the airfoil blade could still be shown to some extent, which hoped to further enhance the aerodynamic efficiency of the VAWT. Additionally, this new type of VAWT has a two dimensional structure for convenient manufacture, which has the latent energy to be popularized.

The vertical axis wind turbine (VAWT) with helical-blade has been developed, manufactured and applied in almost all developed countries. In Indonesia, vertical axis wind turbines are still not widely applied compared to horizontal axis wind turbines. Vertical axis wind turbines with helical-blade are still very rare in Indonesia. Research and development of the vertical axis wind turbine are needed because of its advantages compared to horizontal axis wind turbine. The advantages are: can operate in various wind directions, lower noise due to smaller tip speed ratio (TSR) and for large-scale, mechanical and electrical systems of turbine can be placed on ground. The aim of this research is to design a vertical axis wind turbine rotor with helical-blade that can be applied at low speeds and changing direction wind condition, such as urban wind characteristics. Performance analysis of wind turbine rotor is done by using double-multiple stream-tube (DMS) model approach. This research yields a rotor of vertical axis wind turbine with helical-blade with rotor length and diameter are 2m and 1m respectively, the rotor blade airfoil is DU-06-W-200 with chord length is 0.2m. From analysis, the optimum tip speed ratio of the rotor is 2.6 with a maximum power coefficient is 0.57.

Numerical study of the effect of turbulence intensity on VAWT performance

Within a wind farm, multiple turbine wakes can interact and have a substantial effect on the overall power production. This makes an understanding of the wake recovery process critically important to optimizing wind farm efficiency. Vertical-axis wind turbines (VAWTs) exhibit features that are amenable to dramatically improving this efficiency. However, the physics of the flow around VAWTs is not well understood, especially as it pertains to wake interactions, and it is the goal of this thesis to partially fill this void. This objective is approached from two broadly different perspectives: a low-order view of wind farm aerodynamics, and a detailed experimental analysis of the VAWT wake. One of the contributions of this thesis is the development of a semi-empirical model of wind farm aerodynamics, known as the LRB model, that is able to predict turbine array configurations to leading order accuracy. Another contribution is the characterization of the VAWT wake as a function of turbine solidity. It was found that three distinct regions of flow exist in the VAWT wake: (1) the near wake, where periodic blade shedding of vorticity dominates; (2) a transition region, where growth of a shear-layer instability occurs; (3) the far wake, where bluff-body oscillations dominate. The wake transition can be predicted using a new parameter, the dynamic solidity, which establishes a quantitative connection between the wake of a VAWT and that of a circular cylinder. The results provide insight into the mechanism of the VAWT wake recovery and the potential means to control it.

Investigation of V-shaped blade for the performance improvement of vertical axis wind turbines

Depleting oil reserves and fossil fuels has changed the aspect of thought in energy sector and led to a strong focus on renewable energy sources. Wind energy sector is a potential area of research as the idea of micro grid and domestic power integration are in place. Wind turbines that can be used to harness the low wind velocities for power generation are of importance. Horizontal Axis Wind Turbines and vertical Axis Wind Turbines are the types of wind turbines used to convert wind energy to electrical energy. Horizontal Axis Wind Turbines provide good wind power conversion efficiency and are used in regions of moderate to high wind speeds and in regions of lower wind speeds, Vertical Axis Wind Turbines performance is satisfactory. In this work, the mathematical modeling of HAWT and different types of VAWTs are presented, followed by analysis of those turbine models under lower air velocities. The performance parameters used in this study are maximum power coefficient and output power which are standard performance metrics for wind power generation. The analysis reinforces the fact that, in domestic conditions, where the wind velocity in low, VAWTs provide superior performance.