Challenges in the aerodynamics modeling of an oscillating and translating airfoil at large incidence angles

Ghoreyshi, Mehdi; Cummings, Russell M.

doi:10.1016/j.ast.2012.10.013

Cited by 22 publications

(10 citation statements)

References 51 publications

(57 reference statements)

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“…Because the airfoil is moving, this AoA should be corrected due to the heaving motion with Equation (9), so the controller has to do calculations "on the loop" in order to know this dynamic angle of attack α re f . In reality, the unsteady lift results in being very different to the one described above; it presents non-linearities and hysteresis loops that become very complicated with the online corrections for the dynamic angle of attack, not to mention the effects of the feedback control [44,45].…”

Section: Control Schemementioning

confidence: 99%

Numerical Study of an Oscillating-Wing Wingmill for Ocean Current Energy Harvesting: Fluid-Solid-Body Interaction with Feedback Control

Balam-Tamayo

Málaga

Figueroa-Espinoza

2020

JMSE

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The performance and flow around an oscillating foil device for current energy extraction (a wingmill) was studied through numerical simulations. OpenFOAM was used in order to study the two-dimensional (2D) flow around a wingmill. A closed loop control law was coded in order to follow a reference angle of attack. The objective of this control law is to modify the angle of attack in order to enhance the lift force (and increase power extraction). Dimensional analysis suggests a compromise between the generator (or damper) stiffness and actuator/control gains, so a parametric study was carried out while using a new dimensionless number, called B, which represents this compromise. It was found that there is a maximum on the efficiency curve in terms of the aforementioned dimensionless parameter. The lessons that are learned from this fluid-structure and feedback coupling are discussed; this interaction, combined with the feedback dynamics, may trigger dynamic stall, thus decreasing the performance. Moreover, if the control strategy is not carefully selected, then the energy spent on the actuator may affect efficiency considerably. This type of simulation could allow for the system identification, control synthesis, and optimization of energy harvesting devices in future studies.

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Section: Control Schemementioning

confidence: 99%

Numerical Study of an Oscillating-Wing Wingmill for Ocean Current Energy Harvesting: Fluid-Solid-Body Interaction with Feedback Control

Balam-Tamayo

Málaga

Figueroa-Espinoza

2020

JMSE

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“…All computations are started from a steady-state solution and clean configuration at 0 deg angles of attack and then advanced in time using second-order accuracy with five Newton subiterations. Timestep size is set to 5 × 10 −4 seconds based on a sensitivity study of the grid in [45]. Note that noncirculatory loads occur over a short period of time, and hence a relatively small time step is needed for accurately calculating these loads.…”

Section: Aerodynamic Modeling At α Equal To Zero Degreesmentioning

confidence: 99%

“…As time progresses, the normal force asymptotically reaches the steady-state value at 1 deg flap angle. The initial peak can be explained based on the energy of acoustic wave systems created by the initial grid perturbation [45]. The pitch moment also has an initial negative peak and a transient solution until it reaches the steady-state value.…”

Section: Aerodynamic Modeling At α Equal To Zero Degreesmentioning

confidence: 99%

Unsteady Aerodynamic Modeling of Aircraft Control Surfaces by Indicial Response Methods

Ghoreyshi

Cummings

2014

AIAA Journal

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This study is part of a larger effort to create reduced-order models for aerodynamic forces and moments acting on a maneuvering aircraft with moving control surfaces. The aircraft used in this study was inspired by the T-38 jet trainer and includes elevators, rudder, ailerons, and trailing-edge flaps on the wing for landing and takeoff. A hybrid unstructured overset mesh was generated to move these control surfaces and simulate the unsteady flowfields around the aircraft. The static results are first compared to experimental data available at different flap deflection angles, with good agreement obtained at low to moderate angles of attack and deflection angles. Unsteady airloads predictions were then made using the indicial response methods and response functions due to step changes in control surface deflection angles. A time-dependent surrogate model was also used to approximate the response function variation with changes in the angle of attack. The model outputs were then compared with time-accurate simulations of arbitrary control surface motions within the range of data used for model generation. Very good agreement was found between models and computational-fluid-dynamics data for low and high motion rates at low to moderate deflection angles. The results demonstrated that unsteady effects significantly change the amplitude and phase lags of predicted airloads compared with static (or steady-state) predictions.

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“…Goman and Khrabrov proposed the statespace representation of aerodynamic characteristics at high angles of attack, 11 which is directly amenable to identification and validation from CFD results. 12,13 This paper attempts to investigate the wind tunnel wall interference effects on an oscillating aerofoil in the stall regime as has been accomplished with small amplitude motion. The test case is the two-dimensional NACA0012 aerofoil in the NASA AMRDL-Ames 7 ′ × 10 ′ subsonic wind tunnel, which has a solid wall.…”

Section: Introductionmentioning

confidence: 99%

Wind Tunnel Wall Interference Effects on an Oscillating Aerofoil in the Stall Regime

Cheng

Löwenberg

Wangz

et al. 2015

33rd AIAA Applied Aerodynamics Conference

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In order to extract aerodynamic data from multi-degree-of-freedom wind tunnel tests, it is necessary to account for various interference effects, including those of the tunnel walls. As a precursor to developing a technique for estimating wall interference effects in 3 dimensions, a 2D aerofoil undergoing oscillations in the stall regime is investigated and a means of accounting for the wall interference proposed. Computational fluid dynamics is utilized to obtain the aerodynamic load and its accuracy is assessed by comparison with published experimental data. Besides comparing the pressure distribution and lift force loops, a five parameter Leishman-Beddoes model is identified to fit the computational results. For dynamic experiments, the pressure augmentation is accompanied by an increase in lift slope during the up stroke. When tunnel wall height increases, the capability of tracking static lift tends to be improved and the model overshoot reduces. The present methodology proves to be a reliable approach to evaluate the interference of tunnel walls for 2D wings, and could be used to extrapolate the wind tunnel data to generate a free flight aerodynamic model with a good degree of efficiency and accuracy.

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Challenges in the aerodynamics modeling of an oscillating and translating airfoil at large incidence angles

Cited by 22 publications

References 51 publications

Numerical Study of an Oscillating-Wing Wingmill for Ocean Current Energy Harvesting: Fluid-Solid-Body Interaction with Feedback Control

Numerical Study of an Oscillating-Wing Wingmill for Ocean Current Energy Harvesting: Fluid-Solid-Body Interaction with Feedback Control

Unsteady Aerodynamic Modeling of Aircraft Control Surfaces by Indicial Response Methods

Wind Tunnel Wall Interference Effects on an Oscillating Aerofoil in the Stall Regime

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