Helge Aagaard Madsen

Helge Aagaard Madsen
Technical University of Denmark | DTU · Department of Wind Energy

PhD

About

210
Publications
70,398
Reads
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5,579
Citations
Citations since 2017
69 Research Items
3067 Citations
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20172018201920202021202220230100200300400500600
20172018201920202021202220230100200300400500600
Additional affiliations
March 1984 - present
Technical University of Denmark
Position
  • Researcher
Description
  • Working on engineering modelling of aerodynamics, aeroelasticity and aeroacoustics and big experiments.
Education
June 1979 - June 1982
Aalborg University
Field of study
  • The Actuator Cylinder flow model for Vertical Axis Wind Trubines

Publications

Publications (210)
Article
Full-text available
One promising design solution for increasing the energy production of modern horizontal axis wind turbines is the installation of curved tip extensions. However, since the aeroelastic response of such geometrical add-ons has not been characterized yet, there are currently uncertainties in the application of traditional aerodynamic numerical models....
Preprint
Full-text available
Among a few field experiments on wind turbines for analyzing laminar-turbulent boundary layer transition, the results obtained from the DAN-AERO and aerodynamic Glove projects provide significant findings. The effect of inflow turbulence on the boundary layer transition and the possible transition mechanisms on wind turbine blades are discussed and...
Preprint
Full-text available
One promising design solution for increasing the energy production of modern horizontal axis wind turbines is the installation of curved tip extensions. However, since the aeroelastic response of such geometrical add-ons has not been characterized yet, there are currently uncertainties in the application of traditional aerodynamic numerical models....
Article
Full-text available
We present an autonomous add-on measurement system for detailed aerodynamic measurements on full scale turbines. From the measured data we can derive the local aerodynamic coefficients for the blade section and e.g. compare with wind tunnel data for a similar section. This forms the basis for evaluating how well the airfoil performs on a rotor in t...
Article
Full-text available
The performance of a wind turbine, its aerodynamic and acoustic predictions, and expected power output are affected by atmospheric turbulence. Previous studies showed that the installation of high-frequency measurement devices on blades is needed in order to analyze the effect of the inflow turbulence on boundary layer transition and on noise emiss...
Article
Full-text available
This article describes a field test performed on a 4.3 MW wind turbine with one blade equipped with an active flap system. The results presented focus primarily on the steady state and periodic characterization of the active flap system in different deflection states. The tests were performed between 2020 and 2021 on a test turbine in northern Denm...
Preprint
Full-text available
Wind energy is foundational for achieving 100 % renewable electricity production and significant innovation is required as the grid expands and accommodates hybrid plant systems, energy-intensive products such as fuels, and a transitioning transportation sector. The sizable investments required for wind power plant development and integration make...
Article
Full-text available
Predicting the power and loads of wind turbines in waked inflow conditions still presents a major modelling challenge. It requires the accurate modelling of the atmospheric flow conditions, wakes of upstream turbines and the response of the turbine of interest. Rigorous validations of model frameworks against measurements of utility-scale wind turb...
Preprint
Full-text available
This is a paper we submitted almost 10 years ago. Unfortunately it was not received well by the reviewers. In our opinion it still remains relevant after 10 years.
Article
Full-text available
In this work, a computationally efficient engineering model for the aerodynamics of swept wind turbine blades is proposed for the extended blade element momentum (BEM) formulation. The model is modified based on a coupled near- and far-wake model, in which the near wake is assumed to be the first quarter revolution of the non-expanding helical wake...
Article
This work is part of an ongoing study, creatively named the “LowWind Project” (Madsen et al., 2020), whose goal is to investigate at what price point a hypothetical 3.4 MW 100 W/m2 low wind (LW) turbine with a hub height of 127.5 m, a rotor diameter of 208 m, and a cut-out wind speed of 13 m/s becomes competitive in Northern and Central Europe’s en...
Presentation
Full-text available
The presentation is an update on the work in the LowWind project and presentation of recent findings, September 2021.
Preprint
Full-text available
In this work, a computationally efficient engineering model for the aerodynamics of swept wind turbine blades is proposed for the extended blade element momentum (BEM) formulation. The model is modified based on a coupled near- and far-wake model, in which the near-wake is assumed to be the first quarter revolution of the non-expanding helical wake...
Technical Report
Full-text available
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
Preprint
This work is part of an ongoing study, creatively named the "LowWind Project", which is a collaborative effort between DTU and industry to design and eventually implement a 3.4 MW 100 W/m^2 low wind (LW) turbine with a hub height of 127.5 m, a rotor diameter of 208 m, and a cut-out wind speed of 13 m/s. This paper investigates at what price point t...
Preprint
This work is part of an ongoing study, creatively named the "LowWind Project", which is a collaborative effort between DTU and industry to design and eventually implement a 3.4 MW 100 W/m^2 low wind (LW) turbine with a hub height of 127.5 m, a rotor diameter of 208 m, and a cut-out wind speed of 13 m/s. This paper investigates at what price point t...
Article
Full-text available
This article describes a series of validation tests of an active flap system (AFS) on a multi-megawatt wind turbine. A single blade of a 4 MW turbine with 130 m rotor diameter (SWT-4.0-130) is retrofitted in the outer 15–20 m with the AFS. The AFS is controlled remotely with a pneumatic pressure supply system located in the hub of the turbine. The...
Article
Full-text available
Laminar-turbulent transition behavior of a wind turbine blade section is investigated in this study by means of field experiments and 3-D computational fluid dynamics (CFD) rotor simulations. The power spectral density (PSD) integrals of the pressure fluctuations obtained from the high-frequency microphones mounted on a blade section are analyzed t...
Article
Full-text available
We present the preliminary design of a high capacity LowWind turbine rotor with a specific power of 100 W/ m ² , a rated power of 3.4MW and a 208m diameter rotor. The turbine is designed for optimal system integration and thus with a considerably increased power production at low to medium wind speed and stopped at 13 m/s. The AEP of the turbine, d...
Conference Paper
Full-text available
In this paper, four noise propagation models including the parabolic-equation based WindSTAR model, ray-tracing based Nord2000 model, Danish regulation BEK 135 model and ISO 9613-2 standard model are validated against flow and acoustic measurements of a sound source created from a speaker located at a turbine hub of 109 m height. The flow was measu...
Article
Full-text available
This paper deals with the 3D effects of a vertical-axis wind turbine caused by the tip vortices. In this study, the VAWT rotor is simplified by the infinitely bladed actuator cylinder concept. The loads are prescribed to be uniform and normal to the surface and are distributed between the upwind and downwind half. Depending on the load configuratio...
Article
Full-text available
Since the first commercial projects, the development of vertical-axis wind turbines (VAWTs) has been impeded by the limited understanding and inability to accurately model VAWTs. This paper investigates and compares different aerodynamic modelling techniques for VAWTs in 3D. All considered models are using the same blade-element characteristics but...
Article
Full-text available
This article presents the consolidated results of a comprehensive validation campaign of a pneumatic active flap system (AFS) developed within the scope of the Induflap2 project [1] in a collaboration effort between Siemens Gamesa Renewable Energy A/S (SGRE), the Technical University of Denmark (DTU), and Rehau GmbH. The validation results presente...
Preprint
Full-text available
Abstract. Laminar-turbulent transition behaviour of a wind turbine blade section is investigated in this study by means of field experiments and 3-D computational fluid dynamics (CFD) rotor simulations. The power spectral density (PSD) integrals of the pressure fluctuations obtained from the high frequency microphones mounted on a blade section are...
Preprint
Full-text available
Abstract. This article describes a series of validation tests of an active flap system (AFS) on a multi-MW wind turbine. A single blade of a 4 MW turbine with 130 m rotor diameter (SWT-4.0-130) is retrofitted in the outer 15–20 m with the AFS. The AFS is controlled remotely with a pneumatic pressure supply system located in the hub of the turbine....
Article
Full-text available
We show that the upscaling of wind turbines from rotor diameters of 15–20 m to presently large rotors of 150–200 m has changed the requirements for the aerodynamic blade element momentum (BEM) models in the aeroelastic codes. This is because the typical scales in the inflow turbulence are now comparable with the rotor diameter of the large turbines...
Article
Full-text available
In the present work, various data processing methods for laminar to turbulent transition detection on airfoils are assessed based on experimental data. For this purpose, NACA 63‐418 airfoil profile with surface microphones flush mounted both on the suction and the pressure side is used in the wind tunnel experiments. Reynolds numbers are changed in...
Article
Full-text available
We show that the up-scaling of wind turbines from rotor diameters of 15–20 m to presently large rotors of 150–200 m has changed the requirements for the aerodynamic Blade Element Momentum (BEM) models in the aeroelastic codes. This is because the typical scales in the inflow turbulence are now comparable with the rotor diameter of the large turbine...
Conference Paper
Large-scale floating vertical axis wind turbines have great potential for offshore applications. This paper will review the recent developments for generating torque and controlling vertical-axis wind turbines (VAWTs) specifically for floating applications. The phenomena presented include dynamic stall and pitching of the blades, as well as design...
Presentation
Full-text available
The highest renewable energy (RE) penetration markets in Europe offer important lessons that should be incorporated in the planning and design of the future wind power and grid systems in the transition towards 100% RE. As the overall wind power in a region increases, the value of that wind energy decreases and in some cases grid stability and comp...
Presentation
Full-text available
The objective of the presentatio is to present computations of the optimal spacing and thrust for maximum power production for a row of aligned turbines within a specified maximum length of the row. This will be done for different free wind speeds, number of turbines in the row and ambient turbulence intensities. The model to be used will be the ba...
Article
Full-text available
In this paper, inflow information is extracted from a measurement database and used for aeroelastic simulations to investigate if using more accurate inflow descriptions improves the accuracy of the simulated wind-turbine fatigue loads. The inflow information is extracted from nearby meteorological masts (met masts) and a blade-mounted five-hole pi...
Conference Paper
Full-text available
One of the main uncertainties in airfoil and rotor design is the determination of the position of transition on the blade as this can have considerable influence on the aerodynamic loads and in particular rotor power. Even for simulations on a rotor in uniform, steady inflow the determination of the position of transition is challenging. The atmosp...
Article
In recent years, active flap devices on wind turbine blades have been shown to both reduce peak loads at the tower and extend blade fatigue life. Associated benefits include retrofitting existing tower infrastructure with longer and greater energy-producing blades whilst also extending service life of blades. In the current work, a novel wind turbi...
Presentation
Full-text available
This presentation shows the steps conducted in the development of flap technology from tests of the first prototypes in the laboratory to initial full scale testing. The flap technology development at DTU has been ongoing for more than 10 years. In the last three years the work has been conducted within the INDUFLAP2 project, http://www.induflap.dk...
Article
Full-text available
A wind turbine experiences an overshoot in loading after, for example, a collective step change in pitch angle. This overshoot occurs because the wind turbine wake does not immediately reach its new equilibrium, an effect usually referred to as dynamic inflow. Vortex cylinder models and actuator disc simulations predict that the time constants of t...
Conference Paper
Full-text available
The paper describes a general application of actuator surface theory to model wind turbine rotor aerodynamics. The main subject of the paper is an extension of the well-known actuator disc concept to comprise an actuator surface of arbitrary shape. The starting point of the derivation will be based on the physical conditions on the real rotor revea...
Article
Full-text available
Since the investigation of van Ingen et al., attempts were undertaken to search for laminar parts within the boundary layer of wind turbines operating in the lower atmosphere with much higher turbulence levels than seen in wind tunnels or at higher altitudes where airplanes usually fly. Based on the results of the DAN-Aero experiment and the Aerody...
Article
Full-text available
An industrial active flap concept for wind turbine rotor blades is validated numerically by means of CFD, as well as experimentally in a wind tunnel environment. This paper presents the numerical and experimental results, as well as a discussion regarding the testing of airfoils equipped with active flaps with a highly loaded aft portion. A concept...
Article
Full-text available
Passive load alleviation can be achieved through geometric bend-twist coupling, for example, by sweeping the blade backwards. The influence of the blade sweep on the trailing vorticity and bound vorticity is not modelled in the current fast aeroelastic wind turbine codes suitable for certification. A near wake trailed vorticity model which was coup...
Article
Full-text available
The surface imperfections and the inflow turbulence in real operational conditions can cause significant deviations from the predicted wind turbine aerodynamic performance and energy yield. In this study, particular emphasis was placed on the effect of these parameters on the laminar-turbulent transition on wind turbine blades. For this purpose, th...
Article
Full-text available
Vertical-axis wind turbines (VAWTs) in double-rotor configuration, meaning two rotors in close proximity, have the ability to enhance the power performance. In this study, we work towards the understanding of vertical-axis wind turbines in double-rotor configuration. Numerical simulations are performed to gain insight in the physics behind the doub...
Article
Full-text available
A testing campaign utilizing DTU's outdoor rotating rig is described, where a novel morphing flap system developed in collaboration with the University of Bristol within the INNWIND.eu project has been evaluated and successfully demonstrated. In addition, the aerodynamic performance of ECN's newly designed aerofoil has been evaluated in atmospheric...
Article
Full-text available
The influence of the wake of an upstream turbine impinging another one located further downstream is studied focusing on the latter's noise emission. Measurement data are investigated in the form of surface pressure fluctuations acquired using microphones flush-mounted in a wind turbine blade near its tip, characterizing the noise sources. Numerica...
Article
Full-text available
Aero-elastic solver predictions are compared to measured data from the NENUPHAR's 1HS prototype, with a focus on the blade loads. Two solvers are investigated, namely the HAWC2 solver, and DeepLinesWindTM, respectively based on a linear and a non-linear formulation of the Timoshenko beam theory. Various aerodynamic models are used, from simple Mult...
Article
Full-text available
Design loads on turbines are normally simulated with an aeroelastic model using an engineering BEM type model with the turbulent inflow generated with a turbulence model like the Mann model. There are several fundamental uncertainties in this approach, e.g. how well the unsteady induction in response to the turbulent flow is computed. However, with...
Article
Full-text available
In optimal wind turbine design, there is a compromise between maximizing the energy producing forces and minimizing the absolute peak loads carried by the structures. Active flaps are an attractive strategy because they give engineers greater freedom to vary the aerodynamic forces under any condition. Flaps can be used in a variety of different way...
Article
Full-text available
In this paper, inflow information is extracted from a measurement database and used for aeroelastic simulations to investigate if using more accurate inflow descriptions improves the accuracy of the simulated fatigue loads. The inflow information is extracted from the nearby met masts and a blade-mounted five-hole pitot tube. The met masts provide...
Article
Full-text available
This paper presents a method for obtaining the free-inflow velocities from a 3-D flow sensor mounted on the blade of a wind turbine.From its position on the rotating blade, e.g. one-third from the tip, a blade-mounted flow sensor (BMFS) is able to provide valuable information about the turbulent sheared inflow in different regions of the rotor. At...
Article
Full-text available
A wind turbine experiences an overshoot in loading after for example a collective step change in pitch angle. This overshoot occurs because the wind turbine wake does not immediately reach its new equilibrium, an effect usually referred to as dynamic inflow. Analycal vortex models and actuator disc simulations predict that the time constants of thi...
Article
Full-text available
This paper presents a method for obtaining the free inflow velocities from a 3D flow sensor mounted on the blade of a wind turbine. From its position on the rotating blade, e.g. one third from the tip, a blade mounted flow sensor (BMFS) is able to provide valuable information about the turbulent sheared inflow in different regions of the rotor. At...
Article
Full-text available
Current fast aeroelastic wind turbine codes suitable for certification lack an induction model for standstill conditions. A trailed vorticity model previously used as an addition to a blade element momentum theory based aerodynamic model in normal operation has been extended to allow computing the induced velocities in standstill. The model is vali...
Article
Full-text available
In this paper an alternative method to evaluate power performance and loads on wind turbines using a blade-mounted flow sensor is investigated. The hypothesis is that the wind speed measured at the blades has a high correlation with the power and loads such that a power or load assessment can be performed from a few hours or days of measurements....
Article
Full-text available
In optimal wind turbine design, there is a compromise between maximizing the energy producing forces and minimizing the absolute peak loads carried by the structures. Active flaps are an attractive strategy because they give engineers greater freedom to vary the aerodynamic forces under any condition. Flaps can be used in a variety of different way...
Presentation
Full-text available
Presentation at DANSIS meeting on Fluid Structure Interaction, March 26, 2014
Presentation
Full-text available
Presentation at the EU AVATAR project meeting in Pamplona, April 2017
Article
Full-text available
In this paper an alternative method to evaluate power performance and loads on wind turbines using a blade-mounted flow sensor is investigated. The hypothesis is that the wind speed measured at the blades has a high correlation with the power and loads such that a power or load assessment can be performed from a few hours or days of measurements. I...
Article
Full-text available
This paper presents a comparison between measured and simulated tower loads for the Danish offshore wind farm Nysted 2. Previously, only limited full scale experimental data containing tower load measurements have been published, and in many cases the measurements include only a limited range of wind speeds. In general, tower loads in wake conditio...
Article
Full-text available
Current fast aeroelastic wind turbine codes suitable for certification lack an induction model for standstill conditions. A trailed vorticity model previously used as addition to a blade element momentum theory based aerodynamic model in normal operation has been extended to allow computing the induced velocities in standstill. The model is validat...
Article
In this paper, semi-empirical engineering models for the three main wind turbine aerodynamic noise sources, namely, turbulent inflow, trailing edge and stall noise, are introduced.