Computational Investigations of Small Deploying Tabs and Flaps for Aerodynamic Load Control

Dam, C. P. van; Chow, Raymond; Zayas, Jose R.; Berg, Dale E.

doi:10.1088/1742-6596/75/1/012027

Cited by 39 publications

(14 citation statements)

References 10 publications

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“…In this work, OVERLOW 2.2 [34,35] is used to analyze the devices where the dynamic flaps are modeled using overset meshes. This CFD modeling approach of MiTEs is similar to the work of Kinzel et al [16], and somewhat different to those taken by Chow and van Dam [15], van Dam et al [36], and Coder [17]. The model is based on using the overset mesh method to model the flap dynamics.…”

Section: A Nimierical Model Setupmentioning

confidence: 99%

Active Gurney Flaps: Their Application in a Rotor Blade Centrifugal Field

Palacios

Kinzel

Overmeyer

et al. 2014

Journal of Aircraft

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Miniature trailing-edge effectors are segmented gurney flaps that can deploy to achieve multipurpose functions, such as performance enhancement, noise/vibration control, and/or load control on rotor blades. The unsteady aerodynamics of miniature trailing-edge effectors and a déployable plain flap (with an equivalent lift gain) are quantifled experimentally at a reduced frequency of 0.21 and a Reynolds number of 1 x lO". These experiments are also simulated using computational fluid dynamics. The combination of the wind tunnel experiments and computational fluid dynamics are used to quantify the aerodynamic effects of miniature trailing-edge effector deployment to compare their unsteady aerodynamics to plain flaps, and to evaluate the fluid dynamics of miniature trailing-edge effectors against experimental data. The current experiments display unsteady aerodynamics that corroborate previous computational fluid dynamics flndings that indicate that miniature trailing-edge effectors shed on-surface vortices during deployment, affecting the unsteady aerodynamics of the system. Computational fluid dynamics also predicted that miniature trailing-edge effectors require 1/55 power to deploy compared to a plain-flap configuration. Power reduction is a key attractor for the integration of de vices on smart rotors. This work is concluded with an effort that displays that the low power requirement of miniature trailing-edge effectors enable simple deployment methods, such as the use of pressure differentials inherent to the rotor blades. The proposed pneumatic miniature trailing-edge effector configuration was tested at centrifugal forces representative of helicopter rotor blades.Ci cf" (-norm Cf C CL CM

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Section: A Nimierical Model Setupmentioning

confidence: 99%

Active Gurney Flaps: Their Application in a Rotor Blade Centrifugal Field

Palacios

Kinzel

Overmeyer

et al. 2014

Journal of Aircraft

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“…Active translational microtabs [23][24][25][26][27][28] have been proposed as a viable and an effective device for active load control applications. The concept involves small tabs located near the trailing edge of an airfoil, similar to Gurney fl aps.…”

Section: Classifi Cation: G Te I/d S/umentioning

confidence: 99%

“…Recent numerical efforts have focused on the unsteady load changes that occur during tab deployment and retraction. 28 Wind tunnel experiments can be used to test different tab confi gurations (e.g. tab height, tab location, tab spacing).…”

Section: Microtab Experimentsmentioning

confidence: 99%

An overview of active load control techniques for wind turbines with an emphasis on microtabs

et al. 2009

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This paper outlines the benefi ts and challenges of utilizing active fl ow control (AFC) for wind turbines. The goal of AFC is to mitigate damaging loads and control the aeroelastic response of wind turbine blades. This can be accomplished by sensing changes in turbine operation and activating devices to adjust the sectional lift coeffi cient and/or local angle of attack. Fifteen AFC devices are introduced, and four are described in more detail. Non-traditional trailing-edge fl aps, plasma actuators, vortex generator jets and microtabs are examples of devices that hold promise for wind turbine control. The microtab system is discussed in further detail including recent experimental results demonstrating its effectiveness in a three-dimensional environment. Wind tunnel tests indicated that a nearly constant change in C L over a wide range of angles of attack is possible with microtab control. Using an angle of attack of 5 degrees as a reference, microtabs with a height of 1.5%c were capable of increasing CL by +0.21 (37%) and decreasing CL by −0.23 (−40%). The results are consistent with fi ndings from past two-dimensional experiments and numerical efforts. Through comparisons to other load control studies, the controllable range of this micro-tab system is determined to be suitable for smart blade applications.Equation (1) illustrates that there are several distinct approaches that can be taken to lower the COE. One way is to make more reliable turbines, thereby reducing the downtime and O&M costs. Another is to reduce the amount of materials or improve manufacturing techniques to decrease capital cost. COE can also be reduced by increasing the rotor diameter and turbine size; this has been occurring since the beginning of the commercial wind industry. A larger turbine can capture more energy throughout its lifetime, and although the cost of the turbine will increase and O&M may increase as well, the COE has been declining.Signifi cant growth of wind turbine size and weight over the past few decades has made it impossible to control turbines passively as they were controlled in the past. Modern turbines rely on sophisticated control systems that assure safe and optimal operation under a variety of atmospheric conditions. As turbines grow in size, the structural and fatigue loads become more pronounced. Implementing new and innovative load control techniques could decrease RESEARCH ARTICLE Wind Energ. 2010; 13:239-253

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“…Storms [19] found a lift increase of around 13% for a GF size of 0.5% c with minimal or no drag penalties for low and moderate lift coefficient values. The studies of van Dam et al [20,21], based on the research of Meyer et al [22], studied the effects of serrated and split GFs to avoid the vortex shedding.…”

Section: Introductionmentioning

confidence: 99%

Five Megawatt Wind Turbine Power Output Improvements by Passive Flow Control Devices

et al. 2017

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Abstract:The effects of two types of flow control devices, vortex generators (VGs) and Gurney flaps (GFs), on the power output performance of a multi-megawatt horizontal axis wind turbine is presented. To that end, an improved blade element momentum (BEM)-based solver has been developed and BEM-based computations have been carried out on the National Renewable Energy Laboratory (NREL) 5 MW baseline wind turbine. The results obtained from the clean wind turbine are compared with the ones obtained from the wind turbine equipped with the flow control devices. A significant increase in the average wind turbine power output has been found for all of the flow control device configurations and for the wind speed realizations studied in the present work. Furthermore, a best configuration case is proposed which has the largest increase of the average power output. In that case, increments on the average power output of 10.4% and 3.5% have been found at two different wind speed realizations. The thrust force and bending moment in the root of the blade have also been determined and compared with the values of the clean wind turbine. A residual increase in the bending moment of less than 1% has been found.

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Computational Investigations of Small Deploying Tabs and Flaps for Aerodynamic Load Control

Cited by 39 publications

References 10 publications

Active Gurney Flaps: Their Application in a Rotor Blade Centrifugal Field

Active Gurney Flaps: Their Application in a Rotor Blade Centrifugal Field

An overview of active load control techniques for wind turbines with an emphasis on microtabs

Five Megawatt Wind Turbine Power Output Improvements by Passive Flow Control Devices

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