Identification of airfoil polars from  uncertain experimental measurements

Wang, Chengyu; Campagnolo, Filippo; Bottasso, Carlo L.

doi:10.5194/wes-5-1537-2020

Cited by 10 publications

(6 citation statements)

References 22 publications

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“…The inflow observer described in [17] is used to estimate the local wind speed at each turbine. The method, which has been validated with wind tunnel [18] and field [19] data, employs the power C P and the cone C m coefficients of the G1, derived with the Blade Element Momentum (BEM) model described in [20]. The C P and C m are used to compute lookup tables (LUTs) that return the local wind speed at the azimuthal position occupied by a blade, given the aerodynamic torque and the two out-of-plane bending moments measured on the shaft, as well as the measured rotor speed, blade pitch, and air density.…”

Section: Measured and Estimated Quantitiesmentioning

confidence: 99%

First experimental results on lifetime-aware wind farm control

Braunbehrens,

Anand,

Campagnolo

et al. 2024

J. Phys.: Conf. Ser.

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The study presents the methodology, implementation, and first results of the experimental test of a lifetime-aware wind farm control (WFC) approach. The novel strategy goes beyond the conventional WFC formulations and aims to maximise profit while ensuring fulfilment of a desired lifetime. Damage due to fatigue is formulated using a cost model and is also limited by a lifetime constraint. The control strategy is based on yaw-induced wake steering and utilises a tool chain of power and damage estimators. The experiment was conducted with three model turbines in a boundary layer wind tunnel, which allowed the simulation of a realistic dynamic variation of the wind direction. The novel strategy is compared to conventional greedy operation, as well as to the classical maximum power strategy. The results show that the novel control strategy can improve the economic performance of the farm.

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Section: Measured and Estimated Quantitiesmentioning

confidence: 99%

First experimental results on lifetime-aware wind farm control

Braunbehrens,

Anand,

Campagnolo

et al. 2024

J. Phys.: Conf. Ser.

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“…The error in u pitot is related to the uncertainty associated with the measurements of flow density and dynamic pressure. This latter is measured with a MKS Baratron-Type 226A transducer (Baratron, 2022) with full span equal to 1 Torr, characterized by an accuracy of ±0.4 Pa. Density is instead derived from measurements of air pressure, temperature and humidity, and it is affected by an error equal to ±0.01 kgm 3 (Wang et al, 2020). Torque is measured with a load cell installed on the rotor shaft, and it is affected by an uncertainty of ±0.005 Nm.…”

Section: Wind Tunnel Measurementsmentioning

confidence: 99%

“…The measurement uncertainty on power P = QΩ is derived by adding in quadrature the uncertainties on Q and Ω. Finally, thrust T is obtained by correcting the measurements of the bending moments at tower base by the effects induced by the drag of the tower, nacelle and hub spinner (Wang et al, 2020). The calibration of the load cell at tower base reveled an uncertainty on the thrust of ±0.14 N. In turn, all these effects are used to quantify uncertainties in the tip speed ratio λ, thrust coefficient C T , and yaw-induced power losses η P , again by adding errors in quadrature.…”

Section: Wind Tunnel Measurementsmentioning

confidence: 99%

On the power and control of a misaligned rotor – Beyond the cosine law

Tamaro,

Campagnolo,

Bottasso

2023

Preprint

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Abstract. We present a new model to estimate the performance of a wind turbine operating in misaligned conditions. The model is based on the classic momentum and lifting-line theories, considering a misaligned rotor as a lifting wing of finite span, and accounts for the combined effects of both yaw and uptilt angles. Improving on the classical empirical cosine law in widespread use, the new model reveals the dependency of power not only on the misalignment angle, but also on some rotor design parameters and – crucially – on the way a rotor is governed when it is yawed out of the wind. Additionally, the model also shows that a sheared inflow is responsible for the observed lack of symmetry for positive and negative misalignment angles. Notwithstanding its simplicity and insignificant computational cost, the new proposed approach is in excellent agreement with large eddy simulations (LES) and wind tunnel experiments. Building on the new model, we derive the optimal control strategy for maximizing power on a misaligned rotor. Additionally, we maximize the total power of a cluster of two turbines by wake steering, improving on the solution based on the cosine law.

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“…By this method, the nominal polars are corrected, resulting in tuned aerodynamic characteristics that better reflect the actual conditions on the manufactured rotor. This maximum-likelihood calibration procedure was further improved in Wang et al (2020b), to better account for measurement errors.…”

Section: Numerical Simulations: Polar Identificationmentioning

confidence: 99%

Design, performance and wake characterization of a scaled wind turbine with closed-loop controls

Nanos¹,

Bottasso²,

Campagnolo³

et al. 2021

Preprint

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Abstract. This paper describes the design and characterization of a scaled wind turbine model, conceived to support wake and wind farm control experiments in a boundary layer wind tunnel. The turbine has a rotor diameter of 0.6~meters, and was designed to match the circulation distribution of a target conceptual full-scale turbine at its design tip speed ratio. In order to enable the testing of plant-level control strategies, the model is equipped with closed-loop pitch, torque and yaw control, and is sensorized with integrated load cells, as well as with rotor azimuth and blade pitch encoders. After describing the design of the turbine, its performance and wake characteristics are assessed by conducting experiments in two different wind tunnels, in laminar and turbulent conditions, collecting wake data with different measurement techniques. A large-eddy simulator coupled to an actuator-line model is used to develop a digital replica of the turbine and of the wind tunnel. For increased accuracy, the polars of the low-Reynolds airfoil used in the numerical model are tuned directly from measurements obtained from the rotor in operation in the wind tunnel. Results indicate that the scaled turbine performs as expected, measurements are repeatable and consistent, and the wake appears to have a realistic behavior in line with expectations and with a similar slightly larger scaled model turbine. Furthermore, the predictions of the numerical model are well in line with experimental observations.

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Identification of airfoil polars from uncertain experimental measurements

Cited by 10 publications

References 22 publications

First experimental results on lifetime-aware wind farm control

First experimental results on lifetime-aware wind farm control

On the power and control of a misaligned rotor – Beyond the cosine law

Design, performance and wake characterization of a scaled wind turbine with closed-loop controls

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