Abstract ASME Turbo Expo2011: AFC elements on WT
The paper presents the methodical investigation and evaluation of various AFC solutions by means of extensive literature research and several numerical simulations. The best performing AFC solutions are studied and evaluated in a second step experimentally with constant chord wind tunnel wing sections under steady and unsteady conditions. After these two-dimensional investigations, more realistic configurations are studied in a third phase. This phase includes the integration of the investigated AFC solutions in two different custom wind turbine blade design proposals. Each blade design proposal is simulated with an Active BEM code and their effectiveness, energy capture, load alleviation etc, are assessed in order to identify the advantages and disadvantages of each blade design.
(pdf 47KB)
Erneuerbare Energien Article: Smart WT blades (German Version)
This article describes in brief the research efforts of SMART BLADE GmbH in the direction of "smart rotorblades" and active flow control (AFC). Basic principles of AFC are presented in combination with a description of the current challenges in the field of wind turbine aerodynamics and blade design.
(pdf 1.8MB)
Erneuerbare Energien Article English
The English version of the SMART BLADE article "Go with the flow", published at the 1st Issue of the RENEWABLES INTERNATIONAL magazine (English version of Erneuerbare Energien)
(pdf 334KB)
Abstract EWEA 2011: Active Gurney Flap for WT load alleviation
This paper includes results from experiments with active dynamic load control using microflaps at the trailing edge of wind turbine blades. Thereby the focus of the research was the design of several controllers based on neural networks and the comparison to a conventional PID-Controller. A control system consisting of a force sensor, an angle of attack sensor, a controller and the microflap as an actuator was designed and tested in a wind tunnel. For this purpose a test wing with constant cross section, based on the dedicated wind turbine airfoil AH 93-W-174 [2] was equipped with a trailing edge microflap with a flap-chord of 1.6%c. Measurements were accomplished at the large wind tunnel of the Herman Föttinger Institute (HFI) of TU-Berlin. Wind gusts were simulated by varying the angle of attack of the airfoil model in a range o f -10° to 15° with a maximum angular velocity of 2.2°/s.
(pdf 83KB)
Diploma Thesis: A BEM Based Simulation-Tool for Wind Turbine Blades with Active Flow Control Elements
This thesis describes the development of a software tool which provides a method to investigate the use of different active ow control (AFC) concepts for load reduction and power regulation of wind turbines. The software features an aeroelastic model to calculate the dynamic response of the wind turbine structure. The program is an extension of QBlade, an open-source GUI application for wind turbine calculations.
(pdf 4.3MB)
VDI Article March 2011: Smart Blade VGs
The article describes in brief the development of vortex generators and other passive flow control solutions from the researchers of SMART BLADE GmbH. ** Note: The text is in German **
(pdf 1.1MB)
Abstract ASME Turbo Expo 2010: Roughness Effects on WT Blades
The current paper tries to deal with specific roughness related aspects of wind turbine aerodynamics to be taken into account. The phenomena created by distributed roughness originating from manufacturing processes or accumulated during operation (roughness from contamination and erosion) are briefly explained. A more detailed analysis on known related investigations presents the actual state of the art in the field of aeronautics and wind energy. Wind tunnel roughness experiments and numerical investigations on typical wind turbine airfoils as well as aviation airfoils are briefly described and thoroughly compared to wind turbine power measurements.
(pdf 51KB)
DEWEK 2010: Plasma actuators for WT
This paper investigates the feasibility of flow control using dielectric barrier discharge plasma actuators at the near hub region of wind turbine blades. Thereby the root region of the blade was simulated by a circular cylinder model made of a PVC-tube and a thick cambered airfoil model (DU97W300) made of glass fibre reinforced plastic. Both models were equipped with plasma actuators at different positions in order to realize a high frequency unsteady momentum injection to the boundary layer flow.
(pdf 34KB)
DEWEK 2010: WT Blade with leading edge slat
In order to investigate parametrically the implementation of an auxiliary airfoil at a wind turbine blade root, a precise wind tunnel constant chord test wing was machined based on the DU97W300 airfoil. A full span auxiliary wing was also precisely machined, based on the NACA 22 fixed slat airfoil. Special side plates were fitted to the test wing, which allowed the variation of angle and position of the auxiliary wing. Parametric wind tunnel investigations were performed at the large wind tunnel facilities of the Institute of Fluid Mechanics and Technical Acoustics of TU Berlin.
(pdf 45KB)
AIAA Paper 2010: WT control with high deflection Fexible Flap
The paper presents the test process, methodology and results of wind tunnel test campaigns on the investigation of the flexible flap configuration as a possible means of aerodynamic control of wind turbines. The test campaign took place at the HFI/TU Berlin wind tunnel. Measurements were performed with a model of the DU96W180 airfoil as well as with the modified-DU96W180 test airfoil section equipped with the flexible flap assembly in flow with Reynolds number Re equal to 1.3x10⁶. The flexible flap was tested in various positive and negative deflections in order to extract its complete operational curve.
(pdf 116KB)
