Wind tunnel test on airfoil Risø-B1-18 with an Active Trailing Edge Flap

Wind Energy ◽  
2010 ◽  
Vol 13 (2-3) ◽  
pp. 207-219 ◽  
Author(s):  
Christian Bak ◽  
Mac Gaunaa ◽  
Peter B. Andersen ◽  
Thomas Buhl ◽  
Per Hansen ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Wind Tunnel Test ◽  
Trailing Edge ◽  
Trailing Edge Flap

Wind Tunnel Testing of a Helicopter Rotor Trailing Edge Flap Actuated via Pneumatic Artificial Muscles

2010 ◽  
Author(s):  
Benjamin K. S. Woods ◽  
Norman M. Wereley ◽  
Curt S. Kothera
Keyword(s):  
Wind Tunnel ◽  
Aerodynamic Load ◽  
Artificial Muscles ◽  
Specific Work ◽  
Test Model ◽  
Trailing Edge ◽  
Actuation System ◽  
Wide Range ◽  
Pneumatic Artificial Muscles ◽  
Trailing Edge Flap

A novel active trailing edge flap actuation system is under development. This system differs significantly from previous trailing edge flap systems in that it is driven by a pneumatic actuator technology. Pneumatic Artificial Muscles (PAMs) were chosen because of several attractive properties, including high specific work and power output, an expendable operating fluid, and robustness. The actuation system is sized for a full scale active rotor system for a Bell 407 scale helicopter. This system is designed to produce large flap deflections (±20°) at the main rotor rotation frequency (1/rev) to create large amplitude thrust variation for primary control of the helicopter. Additionally, it is designed to produce smaller magnitude deflections at higher frequencies, up to 5/rev (N+1/rev), to provide vibration mitigation capability. The basic configuration has a pair of Pneumatic Artificial Muscles mounted antagonistically in the root of each blade. A bellcrank and linkage system transfers the force and motion of these actuators to a trailing edge flap on the outboard portion of the rotor. A reduced span wind tunnel test model of this system has been built and tested in the Glenn L. Martin Wind Tunnel at the University of Maryland at wind speeds up to M = 0.3. The test article consisted of a 5-ft long tip section of a Bell 407 rotor blade cantilevered from the base of the tunnel with a 34 in, 15% chord plain flap that was driven by the PAM actuation system. Testing over a wide range of aerodynamic conditions and actuation parameters established the considerable control authority and bandwidth of the system at the aerodynamic load levels available in the tunnel. Comparison of quasi-static experimental results shows good agreement with predictions made using a simple system model.

Wind Tunnel Test on Wind Turbine Airfoil with Adaptive Trailing Edge Geometry

2007 ◽  
Author(s):  
Christian Bak ◽  
Mac Gaunaa ◽  
Peter Andersen ◽  
Thomas Buhl ◽  
Per Hansen ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Wind Turbine ◽  
Wind Tunnel Test ◽  
Trailing Edge ◽  
Edge Geometry ◽  
Wind Turbine Airfoil

Design and Experimental Investigation of a Flexible Trailing Edge for Wind Energy Turbine Blades

2020 ◽  
Author(s):  
Martin Pohl ◽  
Johannes Riemenschneider ◽  
Hans Peter Monner
Keyword(s):  
Wind Tunnel ◽  
Wind Energy ◽  
Turbine Blades ◽  
Free Field ◽  
Electric Energy ◽  
Outer Region ◽  
Load Reduction ◽  
Bending Moments ◽  
Trailing Edge ◽  
Trailing Edge Flap

Abstract The demand of affordable, renewable electric energy is still increasing. Wind energy is seen as one of the most promising resources for future electric energy supply. To reduce the cost of wind energy the dimensions of wind energy turbines are still increasing. This leads to higher power output due to the larger rotor diameters, but also due to the higher wind speeds above the boundary layer. This increase in rotor diameter is achieved at the expense of much higher structural loads especially in the rotor blade root. These loads consist of bending moments, that are mainly caused by gravity, wind shear, gusts and the tower influence to the blade. A reduction of these root bending moments would allow a further increase of the rotor diameter, a longer lifetime or a lighter design and therefore be advantageous for the turbine. Load reduction can be achieved by using a trailing edge flap at the outer region of the blade, comparable to control surfaces of aircraft. This trailing edge is capable of moving several times per blade revolution and allows the manipulation of the flow to alleviate changes in the aerodynamic loading. In contrast to aircraft, sealing against environmental media, such as rain, dust, insects and so on is much more important to allow a high lifetime and low maintenance effort. Therefore, a flexible and gapless morphing trailing edge has been designed within the SmartBlades projects at the German Aerospace Center (DLR) for the mentioned purpose. Based on this design, a demonstrator was built, which was tested in a wind tunnel and on a rotational test site for its performance. The paper will present the approach beginning with some design and modeling considerations of the flexible trailing edge and the demonstrator, which was used for testing. Main focus of the paper is the presentation of results obtained from a wind tunnel experiment at Oldenburg University and the rotational experiment at the field research site of the Technical University in Denmark (DTU). In these experiments, the effectiveness of the trailing edge flap could be demonstrated in the wind tunnel as well as in free field. Based on pressure taps and force sensors, the change in the lift of the airfoil due to the deflection of the flexible trailing edge was measured and the resulting polars are shown in this paper. Furthermore, the result of different simple control strategies for the trailing edge in terms of load reduction at the rotating test rig will be presented.

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