Atmospheric tests of trailing-edge aerodynamic devices

Miller, L. Scott; Huang, Sha; Quandt, G.

doi:10.2172/565655

Cited by 15 publications

(10 citation statements)

References 5 publications

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“…Active load control is one of these avenues that researchers have pursued for wind turbine applications. [1][2][3][4][5][6][7][8][9][10] With such need, many devices have been proposed by other researchers to meet these requirements. Although the sensor and control systems have become realistic, much of the work on active load control devices has focused on systems that must still overcome many other technological hurdles and potentially impractical large energy requ irements.…”

Section: Introductionmentioning

confidence: 99%

On the temporal response of active load control devices

Chow

Dam

2009

Wind Energy

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Flow around airfoils with deploying microtabs and microfl aps (or dynamic Gurney fl ap) have been numerically simulated by solving the unsteady turbulent compressible 2-D Navier-Stokes equations with the OVERFLOW 2 solver. Microtabs and microfl aps on the order of 1%c were installed in the trailing edge region of the symmetric NACA 0012 airfoil using a Chimera or overset grid topology. The devices were deployed on the order of one characteristic time unit, and the unsteady aerodynamic responses of both devices were compared. The two devices appear to affect the fl ow similarly by creating a low pressure region aft of the device and changing the Kutta condition. While initial transients varied, the post-deployment aerodynamic response showed a very similar temporal evolution towards a mean asymptotic solution. Both devices reached 90% of mean steady-state lift values by approximately nine characteristic time units from the onset of deployment. Drag and pitching moments evolved signifi cantly faster. The temporal development of these devices is not governed by near-body effects, and instead is an advection driven process. Microfl ap deployment times of 0.25, 0.50 and 1.00 characteristic time units were also examined. The corresponding mean aerodynamic coeffi cients for the three deployment times were comparable by one characteristic time unit after deployment. Validation studies with experimental results comparing shedding frequencies and Strouhal numbers for static, deployed microtabs and microfl aps were also performed to ensure accurate temporal resolution and convergence of the numerical simulations.

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Section: Introductionmentioning

confidence: 99%

On the temporal response of active load control devices

Chow

Dam

2009

Wind Energy

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“…Another phenomenon that could be possibly causing the decrease in the moment is the formation of strong shed vortices at the newly formed flap tips as shown in Figure 14 as was also noted in [18]. The vortices are similar to the tip vortex created at the end of the blade that induces a decrease in α on the inboard (towards hub) segments of the blade.…”

Section: Effect Of Changing the Flap Anglementioning

confidence: 61%

Development of a Wind Turbine Test Rig and Rotor for Trailing Edge Flap Investigation: Static Flap Angles Case

Abdelrahman¹,

Johnson²

2014

J. Phys.: Conf. Ser.

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Abstract.One of the strategies used to improve performance and increase the life-span of wind turbines is active flow control. It involves the modification of the aerodynamic characteristics of a wind turbine blade by means of moveable aerodynamic control surfaces. Trailing edge flaps are relatively small moveable control surfaces placed at the trailing edge of a blade's airfoil that modify the lift of a blade or airfoil section. An instrumented wind turbine test rig and rotor were specifically developed to enable a wide-range of experiments to investigate the potential of trailing edge flaps as an active control technique. A modular blade based on the S833 airfoil was designed to allow accurate instrumentation and customizable settings. The blade is 1.7 meters long, had a constant 178mm chord and a 6° pitch. The modular aerodynamic parts were 3D printed using plastic PC-ABS material. The blade design point was within the range of wind velocities in the available large test facility. The wind facility is a large open jet wind tunnel with a maximum velocity of 11m/s in the test area. The capability of the developed system was demonstrated through an initial study of the effect of stationary trailing edge flaps on blade load and performance. The investigation focused on measuring the changes in flapwise bending moment and power production for different trailing edge flap spanwise locations and deflection angles. The relationship between the load reduction and deflection angle was linear as expected from theory and the highest reduction was caused by the flap furthest from the rotor center. Overall, the experimental setup proved to be effective in measuring small changes in flapwise bending moment within the wind turbine blade and will provide insight when (active) flap control is targeted.

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“…A brief history of employment of trailing edge flaps on wind turbine can be found in literature [35][36][37]. This concept of applying aerodynamic devices has then been revived with more advanced technology in place and it is taking shape in current wind turbine research field.…”

Section: Aerodynamic Devicesmentioning

confidence: 99%

Fatigue Loads Mitigation on Horizontal Axis Wind Turbines Using Aerodynamic Devices. A Survey

Muiruri¹,

Motsamai²

2017

JESTR

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The paper presents overview of source loads and aerodynamic techniques that are feasible for fatigue load reduction on large horizontal axis wind turbines. The article highlights the effects of increasing wind turbine rotor diameter on fatigue load, and feasible aerodynamic techniques that can be employed to reduce fatigue load. Increased in fatigue load is critical as current and future horizontal wind turbines are designed of large rotor blades. Increase in size of wind turbines has been elicited by highly demand for clean energy nowadays as well as need to decrease the cost of energy per kilo watt. As the rotor diameter increases in size, so do effects of air loads acting on the blades. The pitch control systems installed with a purpose of controlling such effects are approaching their capability limits. They are unable to dump sudden, high varying air loads associated with fluctuating wind speed on time. As these effects occur repeatedly during operation of wind turbines, they can cause premature failure or permanent damage of major components due to fatigue load accumulation. In overall, the service life of wind turbine can drastically reduce or high operational and maintenance costs are likely to rise up due to frequent downfalls of unplanned maintenance schedules. Therefore, alternative methods rather than pitch control are reviewed that can improve wind turbines efficiency. The paper concludes by analyzing possible opportunities in future.

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Atmospheric tests of trailing-edge aerodynamic devices

Cited by 15 publications

References 5 publications

On the temporal response of active load control devices

On the temporal response of active load control devices

Development of a Wind Turbine Test Rig and Rotor for Trailing Edge Flap Investigation: Static Flap Angles Case

Fatigue Loads Mitigation on Horizontal Axis Wind Turbines Using Aerodynamic Devices. A Survey

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