Airfoil optimization for noise emission problem and aerodynamic performance criterion on small scale wind turbines

A free-vortex wake (FVW) model is developed in this paper to analyse the unsteady aerodynamic performance of offshore floating wind turbines. A time-marching algorithm of third-order accuracy is applied in the FVW model. Owing to the complex floating platform motions, the blade inflow conditions and the positions of initial points of vortex filaments, which are different from the fixed wind turbine, are modified in the implemented model. A three-dimensional rotational effect model and a dynamic stall model are coupled into the FVW model to improve the aerodynamic performance prediction in the unsteady conditions. The effects of floating platform motions in the simulation model are validated by comparison between calculation and experiment for a small-scale rigid test wind turbine coupled with a floating tension leg platform (TLP). The dynamic inflow effect carried by the FVW method itself is confirmed and the results agree well with the experimental data of a pitching transient on another test turbine. Also, the flapping moment at the blade root in yaw on the same test turbine is calculated and compares well with the experimental data. Then, the aerodynamic performance is simulated in a yawed condition of steady wind and in an unyawed condition of turbulent wind, respectively, for a large-scale wind turbine coupled with the floating TLP motions, demonstrating obvious differences in rotor performance and blade loading from the fixed wind turbine. The non-dimensional magnitudes of loading changes due to the floating platform motions decrease from the blade root to the blade tip.

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Aerodynamic Performance Analysis of Three Bladed Savonius Wind Turbine With Different Overlap Ratios and at Various Reynolds Number

Volume 5: Energy Systems Analysis, Thermodynamics and Sustainability; NanoEngineering for Energy; Engineering to Address Climate Change, Parts A and B ◽

10.1115/imece2010-40272 ◽

2010 ◽

Cited By ~ 1

Author(s):

Mosfequr Rahman ◽

Khandakar N. Morshed ◽

Ahsan Mian

Keyword(s):

Reynolds Number ◽

Wind Tunnel ◽

Wind Turbine ◽

Wind Turbines ◽

Alternative Energy ◽

Vertical Axis ◽

Aerodynamic Performance ◽

Small Scale ◽

Scale Models ◽

Savonius Wind Turbine

Considerable improvements in the aerodynamic performance of a vertical axis wind turbine (VAWT) can be achieved by integrating computational fluid dynamics (CFD) simulation and wind tunnel investigation in their design improvement. With the growing demand for energy worldwide, conventional sources are becoming more scarce and expensive. Wind is among the most popular and fastest growing sources of alternative energy in the world. It is an inexhaustible, indigenous resource, pollution-free, and available almost any time of the day, especially in coastal regions. Industry experts predict that, with proper development, wind energy could provide 20% of the nation’s energy needs. Vertical axis wind turbines (VAWTs) may be as efficient and practical as, and simpler, and significantly cheaper to build and maintain than, horizontal axis wind turbines (HAWTs). They have other inherent advantages; for example, they always face the wind. VAWTs include both a drag-type configuration, such as the Savonius rotor, and a lift-type configuration, such as the Darrieus rotor. The Savonius wind turbine is the simplest. Its operation depends on the difference in drag force when the wind strikes either the convex or concave part of its semi-cylindrical blades. It is good at self-starting and works independently of wind direction. However, its efficiency is relatively lower than that of the lift-type VAWTs. Due to its simple design and low construction cost, Savonius rotors are primarily used for water pumping and to generate wind power on a small scale and its large starting torque makes it suitable for starting other types of wind turbines that have inferior starting characteristics. Recently, some generators with high torque at low rotational speed, suitable for small-scale wind turbines, have been developed, suggesting that Savonius rotors may yet be used to generate electric power. The main goal of this research work is to improve the aerodynamic performance of the three bladed vertical axis Savonius wind turbine. Based on this goal, the objective of this project is to study the performance characteristics of the Savonius wind turbine scale models both experimentally and numerically. The turbine scale models will have different designs with different overlap ratios (ratio of gap between two adjacent blades and the rotor diameter) and without overlap within three blades. The experimental measurements and testing will be conducted in front of a low speed subsonic wind tunnel at different Reynolds number and the computational fluid dynamic (CFD) flow simulation around those design models will be performed by commercial CFD software FLUENT and GAMBIT.

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Comparative study of airfoil profile effect on the aerodynamic performance of small scale wind turbines

2021 12th International Symposium on Advanced Topics in Electrical Engineering (ATEE) ◽

10.1109/atee52255.2021.9425211 ◽

2021 ◽

Author(s):

Messaoud HAZMOUNE ◽

Gheorghe LAZAROIU ◽

Dana-Alexandra CIUPAGEANU ◽

Mohammed DEBBACHE

Keyword(s):

Comparative Study ◽

Wind Turbines ◽

Aerodynamic Performance ◽

Small Scale

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Aerodynamic Performance of Small-Scale Horizontal Axis Wind Turbines Under Two Different Extreme Wind Conditions

Journal of Thermal Engineering ◽

10.18186/jte.94189 ◽

2015 ◽

Vol 1 (3) ◽

pp. 420 ◽

Cited By ~ 5

Author(s):

Emre Alpman

Keyword(s):

Wind Turbines ◽

Aerodynamic Performance ◽

Horizontal Axis ◽

Small Scale ◽

Extreme Wind ◽

Horizontal Axis Wind Turbines

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Aerodynamic performance simulation of three selected airfoils

Universidad Ciencia y Tecnología ◽

10.47460/uct.v25i111.532 ◽

2021 ◽

Vol 25 (111) ◽

pp. 201-211

Author(s):

Mariana Montenegro Montero ◽

Gustavo Richmond Navarro

Keyword(s):

Renewable Energy ◽

Turbulent Flow ◽

Wind Turbine ◽

Wind Turbines ◽

Aerodynamic Performance ◽

Horizontal Axis ◽

Wind Engineering ◽

Small Scale ◽

Horizontal Axis Wind Turbine ◽

Turbulence Effects

This work presents the lift and drag coefficient curves, as functions of the angle of attack, for the NACA0012, S809 and SG6043 airfoils in turbulent flow conditions. The objective is to identify the airfoil with the best aerodynamic performance under conditions that are descriptive of small scale wind turbine. With the use of OpenFOAM, an analysis was done by numerical simulation. In the case of the NACA0012 airfoil, it was found that the performance is insensitive to the changes in turbulence and the Reynold number. The aerodynamic response of the S809 airfoil is to increase both the drag and lift as the turbulence increases. The SG6043 airfoil responds the best out of the three in turbulent flow, given that the lift curves mostly increase with the turbulence. The curves reported in this work are new and not found in previous literature. Keywords: aerodynamics, lift, drag, turbulence References [1]R. Madriz-Vargas, A. Bruce, M. Watt, L. G. Mogollón and H. R. Álvarez, «Community renewable energy in Panama: a sustainability assessment of the “Bocade Lura” PV-Wind-Battery hybrid power system,» Renewable Energy and Environmental Sustainability, vol. 2, nº 18, pp. 1-7, 2017. https://doi.org/10.1051/rees/2017040. [2]S. Mertenes, «Wind Energy in the Built Environment, » Ph.D. dissertation. Multi-Science, Brentwood, 2006. [3]P. Giguere and M. S. Selig, «New airfoils for small horizontal axis wind turbines,» Journal of Solar Energy Engineering-transactions, vol. 120, pp. 108-114, 1988. https://doi.org/10.1115/1.2888052. [4]A. K. Wright and D. H. Wood, «The starting and low wind speed behaviour of a small horizontal axis wind turbine,» Journal of wind engineering and industrial aerodynamics, vol. 92, nº 14-15, pp. 1265-1279, 2004. https://doi.org/10.1016/j.jweia.2004.08.003. [5]G. Richmond-Navarro, M. Montenegro-Montero and C. Otárola, «Revisión de los perfiles aerodinámicos apropiados para turbinas eólicas de eje horizontal y de pequeña escala en zonas boscosas,» Revista Lasallista de Investigación, vol. 17, nº 1, pp. 233-251, 2020. https://doi.org/10.22507/rli.v17n1a22. [6]A. Tummala, R. K. Velamati, D. K. Sinha, V. Indraja and V. H. Krishna, «A review on small scale wind turbines, » Renewable and Sustainable Energy Reviews,vol. 56, pp. 1351-1371, 2016. https://doi.org/10.1016/j.rser.2015.12.027. [7]L. Pagnini, M. Burlando and M. Repetto, «Experimental power curve of small-size wind turbines in turbulent urban environment,» Applied Energy, vol. 154,pp. 112-121, 2015. https://doi.org/10.1016/j.apenergy. 2015.04.117. [8]W. D. Lubitz, «Impact of ambient turbulence on performance of a small wind turbine,» Renewable Energy, vol. 61, pp. 69-73, 2014. https://doi.org/10.1016/j.renene.2012.08.015. [9]P. Devinant, T. Laverne and J. Hureau, «Experimental study of wind-turbine airfoil aerodynamics in high turbulence, » Journal of Wind Engineering and Industrial Aerodynamics, vol. 90, nº 6, pp. 689-707, 2002. https://doi.org/10.1016/S0167-6105(02)00162-9. [10]C. Sicot, P. Devinant, S. Loyer and J. Hureau, «Rotational and turbulence effects on a wind turbine blade. Investigation of the stall mechanisms,» Journal ofwind engineering and industrial aerodynamics, vol. 96, nº 8-9, pp. 1320-1331, 2008. https://doi.org/10.1016/j.jweia.2008.01.013. [11]C. R. Chu and P. H. Chiang, «Turbulence effects on the wake flow and power production of a horizontal-axis wind turbine,» Journal of Wind Engineering and Industrial Aerodynamics, vol. 124, pp. 82-89, 2014. https://doi.org/10.1016/j.jweia.2013.11.001. [12]Y. Kamada, T. Maeda, J. Murata and Y. Nishida, «Visualization of the flow field and aerodynamic force on a Horizontal Axis Wind Turbine in turbulent inflows,» Energy, vol. 111, pp. 57-67, 2016. https://doi.org/10.1016/j.energy.2016.05.098. [13]Q. A. Li, J. Murata, M. Endo, T. Maeda and Y. Kamada, «Experimental and numerical investigation of the effect of turbulent inflow on a Horizontal Axis WindTurbine (Part I: Power performance),» Energy, vol.113, pp. 713-722, 2016. https://doi.org/10.1016/j.energy.2016.06.138. [14]S. W. Li, S. Wang, J. P. Wang and J. Mi, «Effect of turbulence intensity on airfoil flow: Numerical simulations and experimental measurements,» Applied Mathematics and Mechanics, vol. 32, nº 8, pp. 1029-1038, 2011. https://doi.org/10.1007/s10483-011-1478-8. [15]S. Wang, Y. Zhou, M. M. Alam and H. Yang, «Turbulent intensity and Reynolds number effects on an airfoil at low Reynolds numbers,» Physics of Fluids, vol. 26, nº11, p. 115107, 2014. https://doi.org/10.1063/1.4901969. [16]M. Lin and H. Sarlak, «A comparative study on the flow over an airfoil using transitional turbulence models, » AIP Conference Proceedings, vol. 1738, p.030050, 2016. https://doi.org/10.1063/1.4951806. [17]Langley Research Center, «Turbulence Modelling Resource,» NASA, [Online]. Available: https://turbmodels.larc.nasa.gov/langtrymenter_4eqn.html. [Last access: 08 03 2021].

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On the Application of Active Flow Control to Wind Turbines

ASME-JSME-KSME 2011 Joint Fluids Engineering Conference: Volume 1, Symposia – Parts A, B, C, and D ◽

10.1115/ajk2011-13006 ◽

2011 ◽

Author(s):

Avraham Seifert ◽

Oksana Stalnov ◽

Victor Troshin ◽

Maor Hai Avnaim

Keyword(s):

Boundary Layer ◽

Flow Control ◽

Wind Turbines ◽

Active Flow Control ◽

Speed Ratio ◽

Small Scale ◽

Vertical Axis Wind Turbine ◽

Noise Emission ◽

Power Extraction ◽

Active Flow

This paper reviews recent studies conducted at Tal-Aviv University that were aimed at applying active flow control technology to large and small scale wind turbines with the purpose of improved performance and reduced noise emission. Large wind turbines suffer from degradation of surface quality over the 20 years life span. Premature transition results and promotes early turbulent separation. Energizing the boundary layer with vortex generators (VG’s) and active flow control is studied. While both methods are capable of recovering lost performance, VG’s have an off-design drag penalty, while AFC can be turned off when not needed. It is demonstrated that AFC is highly energy efficient. Small wind turbines suffer from low Reynolds number effects resulting from low wind speed, small chord and low tip speed ratio. Passive and semi-active flow control methods are applied to a small vertical axis wind turbine (VAWT) with the purpose of delaying boundary layer separation via forced transition and transient semi-active fluidic jets. Power extraction at low wind speeds is demonstrated to be greatly improved.

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