Experimental analysis on the dynamic wake of an actuator disc undergoing transient loads

Yu, Wang; Hong, V.W.; Ferreira, Carlos; Kuik, G.A.M. van

doi:10.1007/s00348-017-2432-9

Cited by 17 publications

(19 citation statements)

References 15 publications

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“…Its cross section is a 285×285 cm octagon, and the wind speed ranges from 3 to around 30 m/s. The velocity deviations in the vertical plane measured two meters from the outlet are smaller than 0.5%, and the longitudinal turbulence intensity level is smaller than 0.24% [20]. A CAD model of the setup and the basic dimensions of the wind tunnel model are shown in Fig.…”

Section: Experiments Descriptionmentioning

confidence: 99%

Aerodynamic Model Identification of the Flying V from Wind Tunnel Data

García

2020

Aiaa Aviation 2020 Forum

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The aerodynamic model identification of a novel aircraft configuration known as the "Flying V" is presented. A global longitudinal aerodynamic model is estimated using static wind tunnel data from a 4.6% sub-scale model. The aerodynamic model structure, unknown a priori, is determined from the data using a modified stepwise regression technique. Orthogonal polynomial models using Multivariate Orthogonal Functions and non-orthogonal spline models in the angle-of-attack dimension are defined for the estimation of the measured aerodynamic coefficients. The estimated models are validated against a partition of the data not used for the estimation, which shows that an adequate model fit and good prediction capabilities are attained. Spline models achieve better results in terms of fitting and show a better matching between the estimation and validation data. All estimated models are considered adequate, with a maximum relative Root Mean Square error below 8% for the polynomial models and below 3% for the spline models. Nomenclature Latin Symbols b Wing span of the half model, [m] c Reference chord, [m] C X , C Y , C Z Force coefficients in body axes, [N] C l , C m , C n Moment coefficients in body axes, [N•m] F Force [N] G Orthogonalization matrix J OLS cost function L, M, N Roll, pitch and yaw moment, [N•m] M Moment, [N•m] n Number of regressors in model N Number of samples p j Original regressors, j = 1, 2, ..., n q Dynamic pressure, [kg•m/s 2 ] S Wing area, [m 2 ] v Residual vector V Wind speed, [m/s] V Dimensionless wind speed, [-] x State vector X Regression matrix X, Y, Z Aerodynamic forces in body axes, [N] y Output vector z Measurement vector Greek Symbols α Angle of attack, [deg, rad] δ Control surface deflection [deg] θ Parameter vector ξ j

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Section: Experiments Descriptionmentioning

confidence: 99%

Aerodynamic Model Identification of the Flying V from Wind Tunnel Data

García

2020

Aiaa Aviation 2020 Forum

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“…Even if this kind of inflow is not realistic (wind turbines are immersed in an atmospheric boundary layer characterized by a turbulent shear flow) this idealized inflow was chosen in order to study the effect on the wake of dynamic misalignment independently of any other sources of wake distortion. Based on the actuator disc concept, broadly used in literature [4][5][6][7], the models of wind turbines used in this work are 0.1 m diameter porous discs. The disc porosity is defined as the ratio of the empty surface to the total surface of the disc.…”

Section: Approach and Methodsmentioning

confidence: 99%

Experimental analysis of the wake dynamics of a modelled wind turbine during yaw manoeuvres

Macrì

Coupiac²,

Girard³

et al. 2018

J. Phys.: Conf. Ser.

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Abstract. This work focuses on the dynamic analysis of a modelled wind turbine wake during yaw manoeuvres. Indeed, in the context of wind farm control, misalignment of wind turbines is envisaged as a solution to reduce wind turbine wake interactions, by skewing the wake trajectory. To optimize the control strategies, the aerodynamic response of the wake to this type of yaw manoeuvres, as well as the global load response of the rotor disc of the downstream wind turbine, must be quantified. As a first approach, the identification of the overall system is performed through wind tunnel experiments, using a rotor model based on the actuator disc concept. A misalignment scenario of the upstream wind turbine model is imposed and the wind turbine wake deflection is dynamically captured and measured by the use of Particle Imaging Velocimetry.

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“…A recent PhD thesis by Yu (2018) contains both experimental and numerical investigations of dynamic inflow effects. The experimental investigations use discs with varying porosity (Yu et al, 2017), and the numerical model consists of unsteady vortex rings for the near wake and a vortex cylinder model for the far wake (Yu et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Dynamic inflow effects in measurements and high-fidelity computations

Pirrung

Madsen

2018

Wind Energ. Sci.

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Abstract.A wind turbine experiences an overshoot in loading after, for example, a collective step change in pitch angle. This overshoot occurs because the wind turbine wake does not immediately reach its new equilibrium, an effect usually referred to as dynamic inflow. Vortex cylinder models and actuator disc simulations predict that the time constants of this dynamic inflow effect should decrease significantly towards the blade tip. As part of the NASA Ames Phase VI experiment, pitch steps have been performed on a turbine in controlled conditions in the wind tunnel. The measured aerodynamic forces from these experiments seemed to show much less radial dependency of the dynamic inflow time constants than expected when pitching towards low loading. Moreover the dynamic inflow effect seemed fundamentally different when pitching from low to high loading, and the reason for this behavior remained unclear in previous analyses of the experiment. High-fidelity computational fluid dynamics and free-wake vortex code computations yielded the same behavior as the experiments. In the present work these observations from the experiments and high-fidelity computations are explained based on a simple vortex cylinder wake model.

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Experimental analysis on the dynamic wake of an actuator disc undergoing transient loads

Abstract: for unsteady actuator discs and wind turbines, and are made available in an open source database (see Appendix). List of symbols

Cited by 17 publications

References 15 publications

Aerodynamic Model Identification of the Flying V from Wind Tunnel Data

Aerodynamic Model Identification of the Flying V from Wind Tunnel Data

Experimental analysis of the wake dynamics of a modelled wind turbine during yaw manoeuvres

Dynamic inflow effects in measurements and high-fidelity computations

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