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Dr. Galih Bangga
Institute of Aerodynamics and Gas Dynamics, University of Stuttgart, 70569 Stuttgart, Germany

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0 Aerodynamics
0 Wind Energy
0 CFD
0 Rotor design
0 Flow separation

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Flow separation
Aerodynamics

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Full paper
Published: 05 May 2021 in Advanced Theory and Simulations
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The flow physics of high solidity vertical axis wind turbines (VAWTs) is influenced by the dynamic stall effects. The present study is aimed at investigating the effects of airfoil thickness on the unsteady characteristics of high solidity VAWTs. Seven different national advisory committee for aeronautics (NACA) airfoils (0008, 0012, 0018, 0021, 0025, 0030, 0040) are investigated. A high fidelity computational fluid dynamics (CFD) approach is used to examine the load and flow characteristics in detail. Before the study is undertaken, the CFD simulation is validated with experimental data as well as large eddy simulation results with sound agreement. The investigation demonstrates that increasing the airfoil thickness is actually beneficial not only for suppressing the dynamic stall effects but also to improve the performance of high solidity turbines. Interestingly this is accompanied by a slight reduction in thrust component. The strength and radius of the dynamic stall vortex decrease with increasing airfoil thickness. The airfoil thickness strongly influences the pressure distributions during dynamic stall process, which is driven by the suction peak near the leading edge. The knowledge gained might be used by blade engineers for designing future turbines and for improving the accuracy of engineering models.

ACS Style

Galih Bangga; Surya Hutani; Henidya Heramarwan. The Effects of Airfoil Thickness on Dynamic Stall Characteristics of High‐Solidity Vertical Axis Wind Turbines. Advanced Theory and Simulations 2021, 2000204 .

AMA Style

Galih Bangga, Surya Hutani, Henidya Heramarwan. The Effects of Airfoil Thickness on Dynamic Stall Characteristics of High‐Solidity Vertical Axis Wind Turbines. Advanced Theory and Simulations. 2021; ():2000204.

Chicago/Turabian Style

Galih Bangga; Surya Hutani; Henidya Heramarwan. 2021. "The Effects of Airfoil Thickness on Dynamic Stall Characteristics of High‐Solidity Vertical Axis Wind Turbines." Advanced Theory and Simulations , no. : 2000204.

Journal article
Published: 12 April 2021 in Sustainability
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In the present studies, the effects of Gurney flaps on aerodynamic characteristics of a static airfoil and a rotating vertical axis wind turbine are investigated by means of numerical approaches. First, mesh and time step studies are conducted and the results are validated with experimental data in good agreement. The numerical solutions demonstrate that the usage of Gurney flap increases the airfoil lift coefficient CL with a slight increase in drag coefficient CD. Furthermore, mounting a Gurney flap at the trailing edge of the blade increases the power production of the turbine considerably. Increasing the Gurney flap height further increases the power production. The best performance found is obtained for the maximum height used in this study at 6% relative to the chord. This is in contrast to the static airfoil case, which shows no further improvement for a flap height greater than 0.5%c. Increasing the angle of the flap decreases the power production of the turbine slightly but the load fluctuations could be reduced for the small value of the flap height. The present paper demonstrates that the Gurney flap height for high solidity turbines is allowed to be larger than the classical limit of around 2% for lower solidity turbines.

ACS Style

Yosra Chakroun; Galih Bangga. Aerodynamic Characteristics of Airfoil and Vertical Axis Wind Turbine Employed with Gurney Flaps. Sustainability 2021, 13, 4284 .

AMA Style

Yosra Chakroun, Galih Bangga. Aerodynamic Characteristics of Airfoil and Vertical Axis Wind Turbine Employed with Gurney Flaps. Sustainability. 2021; 13 (8):4284.

Chicago/Turabian Style

Yosra Chakroun; Galih Bangga. 2021. "Aerodynamic Characteristics of Airfoil and Vertical Axis Wind Turbine Employed with Gurney Flaps." Sustainability 13, no. 8: 4284.

Journal article
Published: 07 March 2021 in Processes
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A symmetrical NACA 0018 airfoil is often used in such applications as small-to-medium scale vertical-axis wind turbines and aerial vehicles. A review of the literature indicates a large gap in experimental studies of this airfoil at low and moderate Reynolds numbers in the previous century. This gap has limited the potential development of classical turbulence models, which in this range of Reynolds numbers predict the lift coefficients with insufficiently accurate results in comparison to contemporary experimental studies. Therefore, this paper validates the aerodynamic performance of the NACA 0018 airfoil and the characteristics of the laminar separation bubble formed on its suction side using the standard uncalibrated four-equation Transition SST turbulence model and the unsteady Reynolds-averaged Navier-Stokes (URANS) equations. A numerical study was conducted for the chord Reynolds number of 160,000, angles of attack between 0 and 11 degrees, as well as for the free-stream turbulence intensity of 0.05%. The calculated lift and drag coefficients, aerodynamic derivatives, as well as the location and length of the laminar bubble quite well agree with the results of experimental measurements taken from the literature for validation. A sensitivity study of the numerical model was performed in this paper to examine the effects of the time-step size, geometrical parameters and mesh distribution around the airfoil on the simulation results. The airfoil data sets obtained in this work using the Transition SST and the k-ω SST turbulence models were used in the improved double multiple streamtube (IDMS) to calculate aerodynamic blade loads of a vertical-axis wind turbine. The characteristics of the normal component of the aerodynamic blade load obtained by the Transition SST approach are much better suited to the experimental data compared to the k-ω SST turbulence model.

ACS Style

Krzysztof Rogowski; Grzegorz Królak; Galih Bangga. Numerical Study on the Aerodynamic Characteristics of the NACA 0018 Airfoil at Low Reynolds Number for Darrieus Wind Turbines Using the Transition SST Model. Processes 2021, 9, 477 .

AMA Style

Krzysztof Rogowski, Grzegorz Królak, Galih Bangga. Numerical Study on the Aerodynamic Characteristics of the NACA 0018 Airfoil at Low Reynolds Number for Darrieus Wind Turbines Using the Transition SST Model. Processes. 2021; 9 (3):477.

Chicago/Turabian Style

Krzysztof Rogowski; Grzegorz Królak; Galih Bangga. 2021. "Numerical Study on the Aerodynamic Characteristics of the NACA 0018 Airfoil at Low Reynolds Number for Darrieus Wind Turbines Using the Transition SST Model." Processes 9, no. 3: 477.

Journal article
Published: 11 February 2021 in Energy
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The present paper is intended to assess the ability of the state-of-the-art computational fluid dynamics (CFD) and blade element momentum (BEM) approaches for accurate load predictions on a 2.3 MW wind turbine rotor. Three different cases are considered, a steady uniform inflow condition, a turbulent uniform inflow condition and a turbulent inflow case in combination with shear and yaw. The CFD computations employ a delayed-detached eddy simulation (DDES) approach in combination with a high order (5th) WENO method for flux discretization. The BEM calculations apply several correction factors including recently developed dynamic stall and yaw models. Furthermore, a well established procedure at IAG to set-up BEM calculations consistent to CFD will be presented and verified. The results are compared with the field experimental data of the turbine for these three different flow conditions. The studies show that both CFD and BEM results are in a very good agreement with the experimental data not only on the mean load levels but also with regards to the load fluctuations. The differences between BEM, CFD and experimental data for most radial stations are less than 10%.

ACS Style

Galih Bangga; Thorsten Lutz. Aerodynamic modeling of wind turbine loads exposed to turbulent inflow and validation with experimental data. Energy 2021, 223, 120076 .

AMA Style

Galih Bangga, Thorsten Lutz. Aerodynamic modeling of wind turbine loads exposed to turbulent inflow and validation with experimental data. Energy. 2021; 223 ():120076.

Chicago/Turabian Style

Galih Bangga; Thorsten Lutz. 2021. "Aerodynamic modeling of wind turbine loads exposed to turbulent inflow and validation with experimental data." Energy 223, no. : 120076.

Journal article
Published: 14 January 2021 in Wind Energy Science
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The aeroelastic response of a 2 MW NM80 turbine with a rotor diameter of 80 m and interaction phenomena are investigated by the use of a high-fidelity model. A time-accurate unsteady fluid–structure interaction (FSI) coupling is used between a computational fluid dynamics (CFD) code for the aerodynamic response and a multi-body simulation (MBS) code for the structural response. Different CFD models of the same turbine with increasing complexity and technical details are coupled to the same MBS model in order to identify the impact of the different modeling approaches. The influence of the blade and tower flexibility and of the inflow turbulence is analyzed starting from a specific case of the DANAERO experiment, where a comparison with experimental data is given. A wider range of uniform inflow velocities are investigated by the use of a blade element momentum (BEM) aerodynamic model. Lastly a fatigue analysis is performed from load signals in order to identify the most damaging load cycles and the fatigue ratio between the different models, showing that a highly turbulent inflow has a larger impact than flexibility, when low inflow velocities are considered. The results without the injection of turbulence are also discussed and compared to the ones provided by the BEM code AeroDyn.

ACS Style

Giorgia Guma; Galih Bangga; Thorsten Lutz; Ewald Krämer. Aeroelastic analysis of wind turbines under turbulent inflow conditions. Wind Energy Science 2021, 6, 93 -110.

AMA Style

Giorgia Guma, Galih Bangga, Thorsten Lutz, Ewald Krämer. Aeroelastic analysis of wind turbines under turbulent inflow conditions. Wind Energy Science. 2021; 6 (1):93-110.

Chicago/Turabian Style

Giorgia Guma; Galih Bangga; Thorsten Lutz; Ewald Krämer. 2021. "Aeroelastic analysis of wind turbines under turbulent inflow conditions." Wind Energy Science 6, no. 1: 93-110.

Journal article
Published: 01 December 2020 in Physics of Fluids
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Gust response is one of the classic topics in aerodynamics. Two different transfer functions, Sears and Atassi, have been used to model the unsteady lift responses of an airfoil experiencing a sinusoidal gust over the past few decades. However, a significant discrepancy against measured data has consistently been observed. Although the discrepancy at high frequencies was solved by a correct normalization of the lift response of an airfoil [Wei et al., “Insights into the periodic gust response of airfoils,” J. Fluid Mech. 876, 237 (2019)], totally opposite trends emerged between the experimental data and both functions at low frequencies. To clarify the observed discrepancy, both wind-tunnel experiments and numerical simulations are performed in this study to characterize the Sears and Atassi inflow conditions generated by oscillating grid vanes. A scaling law is established for fast determination of the oscillation parameters of the vanes required to generate a specific gust angle. The gust-angle phase shift between the empty-tunnel and test airfoil cases is quantified. A universal transfer function normalization method is proposed for arbitrary sinusoidal gusts and arbitrary airfoil shapes. The discrepancy between the measured and theoretical lift responses at low gust frequencies is found to be related to the dynamic effect of the highly turbulent wakes of the oscillating vanes as well as the large installation angle of the test airfoil.

ACS Style

Zhenlong Wu; Galih Bangga; Thorsten Lutz; Gerrit Kampers; Michael Hölling. Insights into airfoil response to sinusoidal gusty inflow by oscillating vanes. Physics of Fluids 2020, 32, 125107 .

AMA Style

Zhenlong Wu, Galih Bangga, Thorsten Lutz, Gerrit Kampers, Michael Hölling. Insights into airfoil response to sinusoidal gusty inflow by oscillating vanes. Physics of Fluids. 2020; 32 (12):125107.

Chicago/Turabian Style

Zhenlong Wu; Galih Bangga; Thorsten Lutz; Gerrit Kampers; Michael Hölling. 2020. "Insights into airfoil response to sinusoidal gusty inflow by oscillating vanes." Physics of Fluids 32, no. 12: 125107.

Journal article
Published: 15 September 2020 in Sustainability
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This study investigates the impacts of dierent airfoil shapes on the 3D augmentation and power production of horizontal axis wind turbines (HAWTs). The aerodynamic eect from changing the leading and trailing edge of the airfoil is the emphasis of the research. Varied power produced from modifying sensitivity on 3D augmentations, caused by revamping airfoil shapes, are shown. The 3D correction law, considering the chord to radius ratio and the blades’ pitch angle in the rotation, is applied to the airfoil lift coecients. The blade element method (BEM) embedded in the software Qblade with modified lift coecients simulates the power productions of three wind turbines from these airfoils. The comparisons of the boundary layer characteristics, sectional forces, and inflow angle of the blade sections are calculated. The k-omega SST turbulence model in OpenFoam visualizes the stall and separation of the blades’ 2D section. The airfoils with a rounded leading edge show a reduced stall and separated flow region. The power production is 2.3 times higher for the airfoil constructed with a more rounded leading edge S809r and two times higher for the airfoil S809gx of the symmetric structure.

ACS Style

Youjin Kim; Galih Bangga; Antonio Delgado. Investigations of HAWT Airfoil Shape Characteristics and 3D Rotational Augmentation Sensitivity Toward the Aerodynamic Performance Improvement. Sustainability 2020, 12, 7597 .

AMA Style

Youjin Kim, Galih Bangga, Antonio Delgado. Investigations of HAWT Airfoil Shape Characteristics and 3D Rotational Augmentation Sensitivity Toward the Aerodynamic Performance Improvement. Sustainability. 2020; 12 (18):7597.

Chicago/Turabian Style

Youjin Kim; Galih Bangga; Antonio Delgado. 2020. "Investigations of HAWT Airfoil Shape Characteristics and 3D Rotational Augmentation Sensitivity Toward the Aerodynamic Performance Improvement." Sustainability 12, no. 18: 7597.

Journal article
Published: 20 August 2020 in Wind Energy Science
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Robust and accurate dynamic stall modeling remains one of the most difficult tasks in wind turbine load calculations despite its long research effort in the past. In the present paper, a new second-order dynamic stall model is developed with the main aim to model the higher harmonics of the vortex shedding while retaining its robustness for various flow conditions and airfoils. Comprehensive investigations and tests are performed at various flow conditions. The occurring physical characteristics for each case are discussed and evaluated in the present studies. The improved model is also tested on four different airfoils with different relative thicknesses. The validation against measurement data demonstrates that the improved model is able to reproduce the dynamic polar accurately without airfoil-specific parameter calibration for each investigated flow condition and airfoil. This can deliver further benefits to industrial applications where experimental/reference data for calibrating the model are not always available.

ACS Style

Galih Bangga; Thorsten Lutz; Matthias Arnold. An improved second-order dynamic stall model for wind turbine airfoils. Wind Energy Science 2020, 5, 1037 -1058.

AMA Style

Galih Bangga, Thorsten Lutz, Matthias Arnold. An improved second-order dynamic stall model for wind turbine airfoils. Wind Energy Science. 2020; 5 (3):1037-1058.

Chicago/Turabian Style

Galih Bangga; Thorsten Lutz; Matthias Arnold. 2020. "An improved second-order dynamic stall model for wind turbine airfoils." Wind Energy Science 5, no. 3: 1037-1058.

Preprint content
Published: 17 July 2020
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ACS Style

Galih Bangga. Response to Editor. 2020, 1 .

AMA Style

Galih Bangga. Response to Editor. . 2020; ():1.

Chicago/Turabian Style

Galih Bangga. 2020. "Response to Editor." , no. : 1.

Preprint content
Published: 17 July 2020
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ACS Style

Galih Bangga. Response to Reviewer 2. 2020, 1 .

AMA Style

Galih Bangga. Response to Reviewer 2. . 2020; ():1.

Chicago/Turabian Style

Galih Bangga. 2020. "Response to Reviewer 2." , no. : 1.

Preprint content
Published: 06 July 2020
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ACS Style

Galih Bangga. Final Answer to Reviewer 1. 2020, 1 .

AMA Style

Galih Bangga. Final Answer to Reviewer 1. . 2020; ():1.

Chicago/Turabian Style

Galih Bangga. 2020. "Final Answer to Reviewer 1." , no. : 1.

Preprint content
Published: 30 June 2020
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ACS Style

Galih Bangga. Reply to reviewer 1 - second round. 2020, 1 .

AMA Style

Galih Bangga. Reply to reviewer 1 - second round. . 2020; ():1.

Chicago/Turabian Style

Galih Bangga. 2020. "Reply to reviewer 1 - second round." , no. : 1.

Journal article
Published: 26 June 2020 in Energy
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The present work is intended to assess the ability of state-of-the-art approaches with various fidelity levels for accurate load predictions on vertical axis wind turbines (VAWT). The assessments are conducted by employing the Double-Multiple-Streamtube (DMS), Improved-DMS (IDMS), Unsteady Blade Element Momentum (UBEM), Vortex Model and fully resolved computational fluid dynamics (CFD) approaches. For the later case, three different codes are employed, namely FLOWer, TAU and Ansys Fluent. Three different turbines from low up to high rotor solidity (0.23, 0.53 and 1.325) are selected as the case studies. The prediction results are compared with experimental data at various operating ranges in terms of integral and azimuthal loads. The studies demonstrate that there is consistent agreement between engineering models at lightly loaded cases for the power curve prediction. The discrepancy at high tip speed ratio (λ) is caused by wake expansion, unsteady and decambering effects. In contrast, CFD hardly show consistent power prediction but deliver accurate thrust values.

ACS Style

Galih Bangga; Amgad Dessoky; Zhenlong Wu; Krzysztof Rogowski; Martin O.L. Hansen. Accuracy and consistency of CFD and engineering models for simulating vertical axis wind turbine loads. Energy 2020, 206, 118087 .

AMA Style

Galih Bangga, Amgad Dessoky, Zhenlong Wu, Krzysztof Rogowski, Martin O.L. Hansen. Accuracy and consistency of CFD and engineering models for simulating vertical axis wind turbine loads. Energy. 2020; 206 ():118087.

Chicago/Turabian Style

Galih Bangga; Amgad Dessoky; Zhenlong Wu; Krzysztof Rogowski; Martin O.L. Hansen. 2020. "Accuracy and consistency of CFD and engineering models for simulating vertical axis wind turbine loads." Energy 206, no. : 118087.

Journal article
Published: 19 June 2020 in Energies
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The purpose of this paper is to estimate the H-Darrieus wind turbine aerodynamic performance, aerodynamic blade loads, and velocity profiles downstream behind the rotor. The wind turbine model is based on the rotor designed by McDonnell Aircraft Company. The model proposed here consists of three fixed straight blades; in the future, this model is planned to be developed with controlled blades. The study was conducted using the unsteady Reynolds averaged Navier–Stokes (URANS) approach with the k-ω shear stress transport (SST) turbulence model. The numerical two-dimensional model was verified using two other independent aerodynamic approaches: a vortex model and the extended version of the computational fluid dynamics (CFD) code FLOWer. All utilized numerical codes gave similar result of the instantaneous aerodynamic blade loads. In addition, steady-state calculations for the applied airfoils were also made using the same numerical model as for the vertical axis wind turbine (VAWT) to obtain lift and drag coefficients. The obtained values of lift and drag force coefficients, for a Reynolds number of 2.9 million, agree with the predictions of the experiment and XFOIL over a wide range of angle of attack. A maximum rotor power coefficient of 0.5 is obtained, which makes this impeller attractive from the point of view of further research. Research has shown that, if this rotor were to work with fixed blades, it is recommended to use the NACA 1418 airfoil instead of the original NACA 0018.

ACS Style

Krzysztof Rogowski; Martin Otto Laver Hansen; Galih Bangga. Performance Analysis of a H-Darrieus Wind Turbine for a Series of 4-Digit NACA Airfoils. Energies 2020, 13, 3196 .

AMA Style

Krzysztof Rogowski, Martin Otto Laver Hansen, Galih Bangga. Performance Analysis of a H-Darrieus Wind Turbine for a Series of 4-Digit NACA Airfoils. Energies. 2020; 13 (12):3196.

Chicago/Turabian Style

Krzysztof Rogowski; Martin Otto Laver Hansen; Galih Bangga. 2020. "Performance Analysis of a H-Darrieus Wind Turbine for a Series of 4-Digit NACA Airfoils." Energies 13, no. 12: 3196.

Preprint content
Published: 10 June 2020
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ACS Style

Galih Bangga. Response to Reviewer 1. 2020, 1 .

AMA Style

Galih Bangga. Response to Reviewer 1. . 2020; ():1.

Chicago/Turabian Style

Galih Bangga. 2020. "Response to Reviewer 1." , no. : 1.

Preprint content
Published: 05 May 2020
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Robust and accurate dynamic stall modeling remains one of the most difficult tasks in wind turbine load calculations despite its long research effort in the past. In the present paper, a new second order dynamic stall model is developed with the main aim to model the higher harmonics of the vortex shedding while retaining its robustness for various flow conditions and airfoils. Comprehensive investigations and tests are performed by varying many flow parameters. The occurring physical characteristics for each case are discussed and evaluated in the present studies. The improved model is also tested on four different airfoils with different relative thicknesses. The validation against measurement data demonstrates that the improved model is able to reproduce the dynamic polar accurately without airfoil specific parameter calibration for each investigated flow condition and airfoil. This can deliver further benefit to industrial applications where experimental/reference data for calibrating the model is not always available.

ACS Style

Galih Bangga; Thorsten Lutz; Matthias Arnold. An improved second order dynamic stall model for wind turbine airfoils. 2020, 1 -36.

AMA Style

Galih Bangga, Thorsten Lutz, Matthias Arnold. An improved second order dynamic stall model for wind turbine airfoils. . 2020; ():1-36.

Chicago/Turabian Style

Galih Bangga; Thorsten Lutz; Matthias Arnold. 2020. "An improved second order dynamic stall model for wind turbine airfoils." , no. : 1-36.

Research article
Published: 12 March 2020 in Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy
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Gust is a common atmospheric condition encountered by wind turbines. Despite the presence of a vast amount of literature on this topic, few of them involve lateral gust influence. Due to this motivation, this paper presents an investigation on the effects of sinusoidal gusts on a three-bladed vertical axis wind turbine under varying gust parameters including gust direction, velocity amplitude, and frequency. The chimera mesh technique is used to model the real rotation of the rotor, as well as the resolved gust approach model in the DLR (German Aerospace Center) TAU code for gust simulation. Both the general aerodynamic computational fluid dynamics model and the gust model are validated before the following simulations. Numerous new flow phenomena and physics are revealed. The influences of gust on the rotor power output and flowfield characteristics are discussed and analyzed in detail. The findings in this study may be helpful for some practical wind engineering applications, such as atmospheric influence evaluation and field site selection.

ACS Style

Zhenlong Wu; Qiang Wang; Galih Bangga; Hao Huang. Responses of vertical axis wind turbines to gusty winds. Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 2020, 235, 81 -93.

AMA Style

Zhenlong Wu, Qiang Wang, Galih Bangga, Hao Huang. Responses of vertical axis wind turbines to gusty winds. Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy. 2020; 235 (1):81-93.

Chicago/Turabian Style

Zhenlong Wu; Qiang Wang; Galih Bangga; Hao Huang. 2020. "Responses of vertical axis wind turbines to gusty winds." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 235, no. 1: 81-93.

Preprint content
Published: 19 February 2020
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The aero-elastic response of the DANAERO wind turbine and interaction phenomena are investigated by the use of a high-fidelity model. A time-accurate unsteady fluid-structure interaction (FSI) coupling between a computational fluid dynamics (CFD) code for the aerodynamic response and a multi-body simulation (MBS) code for the structural response is used. Different CFD models of the same turbine with increasing complexity and technical details are coupled to the same MBS model in order to identify the impact of the different modeling approaches. The influence of the blade and tower flexibility and of the inflow turbulence is analyzed for a specific case of the DANAERO experiment. Lastly a fatigue analysis is performed from load signals in order to identify the most damaging load cycles and the fatigue ratio between the different models, showing that for low inflow velocities, a high turbulence has a major impact than the flexibility.

ACS Style

Giorgia Guma; Galih Bangga; Thorsten Lutz; Ewald Krämer. Aero-elastic analysis of wind turbines under turbulent inflow conditions. 2020, 2020, 1 -20.

AMA Style

Giorgia Guma, Galih Bangga, Thorsten Lutz, Ewald Krämer. Aero-elastic analysis of wind turbines under turbulent inflow conditions. . 2020; 2020 ():1-20.

Chicago/Turabian Style

Giorgia Guma; Galih Bangga; Thorsten Lutz; Ewald Krämer. 2020. "Aero-elastic analysis of wind turbines under turbulent inflow conditions." 2020, no. : 1-20.

Preprint content
Published: 16 December 2019
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The purpose of this paper is to estimate the H-Darrieus wind turbine aerodynamic performance, aerodynamic blade loads and velocity profiles downstream behind the rotor. The wind turbine model is based on the rotor designed by McDonnell Aircraft Company. The model proposed here consists of three fixed straight blades; in the future this model is planned to be develop with controlled blades. The study was conducted using the unsteady Reynolds averaged Navier-Stokes (URANS) approach with the k-ω shear stress transport (SST) turbulence model. The numerical two-dimensional model was verified using two other independent aerodynamic approaches: the vortex model developed in Technical University of Denmark (DTU) and the extended version of the CFD code FLOWer at the University of Stuttgart (USTUTT). All utilized numerical codes gave similar result of the instantaneous aerodynamic blade loads. In addition, steady-state calculations for the applied airfoils were also made using the same numerical model as for the vertical axis wind turbine (VAWT) to obtain lift and drag coefficients. The obtained values of lift and drag force coefficients, for a Reynolds number of 2.9 million, agree with the predictions of the experiment and XFoil over a wide range of angle of attack. The maximum rotor power coefficients are obtained at 0.5, which makes this impeller attractive from the point of view of further research. This work also addresses the issue of determining the aerodynamic performance of the rotor with various 4-digit NACA airfoils. The effect of two airfoil parameters, maximum airfoil thickness and maximum camber, on aerodynamic rotor performance is investigated. Research has shown that if this rotor were to work with fixed blades it is recommended to use the NACA 1418 airfoil instead of the original NACA 0018.

ACS Style

Krzysztof Rogowski; Martin Otto Laver Hansen; Galih Bangga. Performance analysis of a Darrieus-type wind turbine for a series of 4-digit NACA airfoils. 2019, 2019, 1 -30.

AMA Style

Krzysztof Rogowski, Martin Otto Laver Hansen, Galih Bangga. Performance analysis of a Darrieus-type wind turbine for a series of 4-digit NACA airfoils. . 2019; 2019 ():1-30.

Chicago/Turabian Style

Krzysztof Rogowski; Martin Otto Laver Hansen; Galih Bangga. 2019. "Performance analysis of a Darrieus-type wind turbine for a series of 4-digit NACA airfoils." 2019, no. : 1-30.

Research article
Published: 13 September 2019 in SN Applied Sciences
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The present studies investigate the performance of a small Savonius vertical axis wind turbine equipped with an upstream obstacle to guide the wind direction. The wind tunnel measurement was carried out in a test facility at the Mechanical Engineering Department, Institut Teknologi Sepuluh Nopember (ITS). The dynamic torque was measured using the brake dynamometer. Several variations of the obstacle orientations were investigated. Two different wind speeds of 2.48 m/s and 7.45 m/s were considered, that correspond to the Reynolds numbers of 30,000 and 90,000, respectively, according to the rotor diameter. It is found from the studies that the mechanical torque and power generated by the rotor are strongly affected by the obstacle. On the other hand, the Reynolds number has no significant impact on the rotor performance.

ACS Style

Nabila Prastiya Putri; Triyogi Yuwono; Jasmi Rustam; Prayogi Purwanto; Galih Bangga. Experimental studies on the effect of obstacle upstream of a Savonius wind turbine. SN Applied Sciences 2019, 1, 1216 .

AMA Style

Nabila Prastiya Putri, Triyogi Yuwono, Jasmi Rustam, Prayogi Purwanto, Galih Bangga. Experimental studies on the effect of obstacle upstream of a Savonius wind turbine. SN Applied Sciences. 2019; 1 (10):1216.

Chicago/Turabian Style

Nabila Prastiya Putri; Triyogi Yuwono; Jasmi Rustam; Prayogi Purwanto; Galih Bangga. 2019. "Experimental studies on the effect of obstacle upstream of a Savonius wind turbine." SN Applied Sciences 1, no. 10: 1216.