Galih Bangga

Det Norske Veritas | DNV

The present studies are specifically aimed at investigating the sensitivity of different dynamic stall models when exposed to various excitation frequencies targeted at the blade edgewise vibrations. The work is done on a modified version of the IEA 15 MW reference wind turbine employing a wind turbine design tool Bladed. The state-of-the-art dynam...

The study presents a systematic comparison between two of the most-credited dynamic stall models for wind turbine applications: the original Beddoes-Leishman (BL) model and the newly-developed IAG. The scope of such comparison, supported by experimental data, is to shed new light on the actual suitability of current dynamic stall models for their i...

The present work is aimed specifically at providing an order of estimate of the load changes due to the inclusion of unsteady aerodynamic effects. Two dynamic stall models are assessed: (1) the incompressible version of the Beddoes-Leishman model and (2) the newly developed IAG dynamic stall model. Two sets of attached flow constants are considered...

A segregated approach with either synthetically generated velocity fluctuations or a precursor Large-Eddy Simulation (LES) of the atmospheric boundary layer (ABL) and a subsequent hybrid RANS/LES (HRLS) of the resolved rotor is presented in this paper. At first the approach is validated with synthetically generated velocity fluctuations that resemb...

Within an international collaboration framework, the accuracy of rotor aerodynamic models used for design load calculations of wind turbines is being assessed. Where the use of high-fidelity computation fluid dynamics (CFD) and mid-fidelity free-vortex wake (FVW) models has become commonplace within the wind energy community, these still fail to me...

A new framework “BladedFarmWake” to include the upstream wake effects into a wind turbine design tool Bladed was developed in the present work. The effects of neighboring turbines in a wind farm are extracted from a wind farm flow solver LongSim, which has been developed for designing wind farm controllers and evaluating wind farm performance, taki...

This paper presents comprehensive investigations into idling instability occurring on the IEA 15 MW reference turbine. The systematic studies are carried out by means of Blade Element Momentum (BEM) and free wake vortex (Vortexline) methods. Two state-of-the-art dynamic stall models are tested in the present investigations, namely the Beddoes-Leish...

An impulse turbine uses drag force on its blades to produce torque on its rotor. As fluid flows over the blades, pressure changes occur at the nozzle, which increases the fluid's velocity and reduces the static pressure at the nozzle outlet. The high-momentum fluid then impinges on the rotor blades, generating frictional force and resulting in torq...

Considering the dynamic stall effects in engineering calculations is essential for correcting the aerodynamic loads acting on wind turbines, both during power production and stand-still cases, and impacts significantly the turbine aeroelastic stability. The employed dynamic stall model needs to be accurate and robust for a wide range of airfoils an...

Considering the dynamic stall effects in engineering calculations is essential for correcting the aerodynamic loads acting on wind turbines, both during power production and stand-still cases, and impacts significantly the turbine aeroelastic stability. The employed dynamic stall model needs to be accurate and robust for a wide range of airfoils an...

Within the framework of the fourth phase of the International Energy Agency (IEA) Wind Task 29, a large comparison exercise between measurements and aeroelastic simulations has been carried out featuring three simulation cases in axial, sheared and yawed inflow conditions. Results were obtained from more than 19 simulation tools originating from 12...

Gust is a common atmospheric turbulence phenomenon encountered by aircraft and is one major cause of several undesired instability problems. Although the response of aircraft to the incoming gust has been widely investigated within the subject of external-flow aerodynamics in the past decades, little attention is paid to its effects on the internal...

Wind turbines often have lower performance and experience higher loading in real operation compared to the original design performance. The reasons stem from the influences of complex atmospheric turbulence, blade contamination, surface imperfection and airfoil‐shape changes. Engineering models used for designing wind turbines are limited to inform...

As countries seek clean, renewable, low-cost, domestic alternatives to fossil fuels, wind energy is an increasingly important source of power generation worldwide. Scientists and industry professionals require better tools to understand and expand the performance and efficiency. Wind Turbine Aerodynamics Modeling Using CFD Approaches provides a com...

As countries seek clean, renewable, low-cost, domestic alternatives to fossil fuels, wind energy is an increasingly important source of power generation worldwide. Scientists and industry professionals require better tools to understand and expand the performance and efficiency. Wind Turbine Aerodynamics Modeling Using CFD Approaches provides a com...

As countries seek clean, renewable, low-cost, domestic alternatives to fossil fuels, wind energy is an increasingly important source of power generation worldwide. Scientists and industry professionals require better tools to understand and expand the performance and efficiency. Wind Turbine Aerodynamics Modeling Using CFD Approaches provides a com...

As countries seek clean, renewable, low-cost, domestic alternatives to fossil fuels, wind energy is an increasingly important source of power generation worldwide. Scientists and industry professionals require better tools to understand and expand the performance and efficiency. Wind Turbine Aerodynamics Modeling Using CFD Approaches provides a com...

As countries seek clean, renewable, low-cost, domestic alternatives to fossil fuels, wind energy is an increasingly important source of power generation worldwide. Scientists and industry professionals require better tools to understand and expand the performance and efficiency. Wind Turbine Aerodynamics Modeling Using CFD Approaches provides a com...

As countries seek clean, renewable, low-cost, domestic alternatives to fossil fuels, wind energy is an increasingly important source of power generation worldwide. Scientists and industry professionals require better tools to understand and expand the performance and efficiency. Wind Turbine Aerodynamics Modeling Using CFD Approaches provides a com...

As countries seek clean, renewable, low-cost, domestic alternatives to fossil fuels, wind energy is an increasingly important source of power generation worldwide. Scientists and industry professionals require better tools to understand and expand the performance and efficiency. Wind Turbine Aerodynamics Modeling Using CFD Approaches provides a com...

As countries seek clean, renewable, low-cost, domestic alternatives to fossil fuels, wind energy is an increasingly important source of power generation worldwide. Scientists and industry professionals require better tools to understand and expand the performance and efficiency. Wind Turbine Aerodynamics Modeling Using CFD Approaches provides a com...

To enable the fast growth of the floating offshore wind industry, simulation models must be validated with experimental data. Floating wind model-scale experiments in wind–wave facilities have been performed over the last two decades with varying levels of fidelity and limitations. However, the turbine controls in these experiments have considered...

While modern wind turbines have become by far the largest rotating machines on Earth with further upscaling planned for the future, a renewed interest in small wind turbines (SWTs) is fostering energy transition and smart grid development. Small machines have traditionally not received the same level of aerodynamic refinement as their larger counte...

Wind energy research plays a vital role in the possibility of the success story of wind energy as one of the most promising sustainable energy sources. This continuous process has been achieved from the era of small wind turbines to the current Multi-MW standard and beyond. In this editorial paper, the progress and future outlook of wind energy res...

Rooftop photovoltaic (PV) plant is one ot the independent electricity that us favorable in recent year. Rooftop PV plant can be used as the source of smart building as well as fast charging station. Although rooftop PV plant could provide clean and sustainable energy from solar, they also come with disadvantages in term of intermittent power output...

Within the framework of the fourth phase of International Energy Agency IEA Wind Task 29, a large comparison exercise between measurements and aero-elastic simulations has been carried out featuring three simulation cases in axial, sheared and yawed inflow conditions. Results were obtained from more than 19 simulation tools originating from 12 inst...

While modern wind turbines have become by far the largest rotating machines on Earth with further upscaling planned for the future, a renewed interest in small wind turbines is fostering energy transition and smart grid development. Small machines have traditionally not received the same level of aerodynamic refinement of their larger counterparts,...

Data driven approaches are utilized for optimal sensor placement as well as for velocity prediction of wind turbine wakes. In this work, several methods are investigated for suitability in the clustering analysis and for predicting the time history of the flow field. The studies start by applying a proper orthogonal decomposition (POD) technique to...

The results of high fidelity aerodynamic and acoustic computations of thick flatback airfoils are reported in the present paper. The studies are conducted on a flatback airfoil having a relative thickness of 30% with the blunt trailing edge thickness of 10% relative to chord. Delayed Detached‐Eddy Simulation (DDES) approaches in combination with hi...

This paper present finite element analysis on the internal structure of wind turbine to examined the deflection and stress distribution. The structure was modeled as a cantilever box beam with constant cross section along the length. The dimension of the structure was set according to the original design of the 10 MW AVATAR (Advanced Aerodynamic To...

Accurate computation of the performance of a horizontal-axis wind turbine (HAWT) using Blade Element Momentum (BEM) based codes requires good quality aerodynamic characteristics of airfoils. This paper shows a numerical investigation of transitional flow over the DU 91-W2-250 airfoil with chord-based Reynolds number ranging from 3 × 106 to 6 × 106....

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, 00...

This report describes the results of the fourth phase of IEA TCP Wind Task 29 on wind turbine aerodynamics. The full text is available at http://dx.doi.org/10.5281/zenodo.4817875

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 demonstrat...

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 classica...

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...

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) cod...

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...

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...

Dynamic stall modeling remains one of the most difficult topic in wind turbine aerodynamics despite its long research effort in the past. In the present studies, comprehensive investigations involving CFD, engineering models and experimental data were performed within the joint collaborative work DSWind. Both static and dynamic characteristics of a...

The root area of a wind turbine rotor is usually constructed by very thick airfoils with a relative thickness of more than 35%. An airfoil at that thickness is characterized with strong flow separation. To solve this issue, vortex generators can be used as an active control in order to stabilize the airflow and improve the aerodynamic performance,...

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...

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 p...

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 resol...

Abstract. 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 f...

Modern and larger horizontal-axis wind turbines with power capacity reaching 15 MW and rotors of more than 235-meter diameter are under continuous development for the merit of minimizing the unit cost of energy production ($/Kw.hrs). In this context, the European Wind Energy Association has set a target of installed capacity of 150 GW by 2030, whic...

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...

Abstract. 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 r...

The results of two different numerical techniques, Unsteady Reynolds Averaged Navier Stokes and Delayed Detached Eddy Simulation, are compared to determine their accuracy in the prediction of aerodynamic and aeroacoustic performance of Darrieus vertical axis wind turbines. The flux for URANS simulations is computed using the central differencing sc...

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 pla...

Conference WESC-2019 Session No. 2.8b. MS: Modelling Vertical Axis Wind Turbines Chair: Dr. Martin O.L. Hansen Presentation title: "Performance analysis of a Darrieus-type wind turbine for six four-digit airfoils of NACA series"

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 b...

Wind turbine size increases significantly nowadays to supply the clean energy demand, enforcing blade designers to utilize thick airfoils with reduced aerodynamic efficiency. Systematic studies are needed for performance improvement without sacrificing the structural constraints. Design proposals of the attempts carried out at IAG are presented. Th...

With the growing need for renewable energy, the size of wind turbines is significantly increasing nowadays. This enforces blade designers to employ much thicker airfoils than conventional turbines to provide the necessary structural strength with reduced aerodynamic performance. In the present work, a numerical optimization process employing a gene...

Accurate predictions on vertical axis wind turbine performance are important for the design process but also challenging because the flow is highly unsteady involving a strong variation of the angle of incidence. In the present work, a double-multiple-streamtube (DMS) approach is improved by analytical corrections. First, two-dimensional and three-...

Investigations of active flow control (AFC) using steady and unsteady sinusoidal blowing jet on thick wind turbine airfoils are performed. The focus is on improving the performance of the DU 00‐W2‐401 airfoil through parametric study and to discuss the effectiveness of optimized configuration. The unsteady Reynolds‐Averaged Navier‐Stokes (URANS) an...

The aerodynamic and aeroacoustic behaviors of the Darrieus vertical axis wind turbine are very complicated. Hence, it is challenging to simulate the real flow behavior using the computational fluid dynamics approach. In the present study, the behavior of two different numerical techniques, Unsteady Reynolds Averaged Navier Stokes and Delayed Detach...

The present paper investigates the aerodynamic and aeroacoustic characteristics of H-rotor Darrieus vertical axis wind turbine combined with a promising energy conversion technology, namely wind-lens, employing computational approaches. The Darrieus turbine adequate for low wind speed and urban area conditions. However, its aerodynamic and aeroacou...

The present work delivers an evaluation of the S809 airfoil under static and dynamic conditions employing a computational fluid dynamics (CFD) approach. Pitching motions with three different mean angles of attack, 8°, 14° and 20°, with a reduced frequency of 0.079 and amplitude of 10° were imposed at a quarter chord position. Two widely used eddy-v...

The hydrodynamics of non-reactive and reactive distillation sieve tray columns are analyzed in this study. The first mentioned task was performed in order to verify the accuracy of Computational Fluid Dynamics (CFD) simulation in modeling the flow behavior of a sieve tray system. For the reactive distillation system, the studies were performed for...

With increasing span or wing loading, it becomes increasingly difficult to fulfill all CS22 certification requirements for airbrakes simultaneously. Aerodynamic forces upon Schempp-Hirth airbrakes usually create pilot control forces, which limit the size of the airbrake. A certain design of the airbrake allows to reduce the aerodynamic source of th...

The present studies deliver the computational investigations of a 10 MW turbine with a diameter of 205.8 m developed within the framework of the AVATAR (Advanced Aerodynamic Tools for Large Rotors) project. The simulations were carried out using two methods with different fidelity levels, namely the computational fluid dynamics (CFD) and blade elem...

The present studies deliver the computational investigations of a 10 MW turbine with a diameter of 205.8 m developed within the framework of the AVATAR (Advanced Aerodynamic Tools for Large Rotors) project. The simulations were carried out using two methods with different fidelity levels, namely the computational fluid dynamics (CFD) and blade elem...

Numerical simulations were carried out for the flow field around various diffuser type structures to improve the performance of a small wind turbine rotor. The present studies specifically investigate the effect of four different shapes of diffuser, namely flat diffuser, curved diffuser, flat diffuser with inlet shroud, and curved diffuser with inl...

This paper focuses on the development of an approach for solving nonlinear mechanical maglev oscillation systems. The original physical information included in the governing equations is mostly transferred into analytical and numerical solutions. The analytical method based on the Lindstedt’s perturbation method is used and compared to general nume...