Combined Numerical and Experimental Study on the Use of Gurney Flaps for the Performance Enhancement of NACA0021 Airfoil in Static and Dynamic Conditions

Balduzzi, Francesco; Holst, David C.; Melani, Pier Francesco; Wegner, Felix K.; Nayeri, Christian Navid; Ferrara, Giovanni; Paschereit, Christian Oliver; Bianchini, Alessandro

doi:10.1115/1.0002992v

Cited by 5 publications

(9 citation statements)

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“…In particular, a two-dimensional unsteady Reynolds-Averaged Navier-Stokes (URANS) approach has been used. The polar data for the eroded airfoils equipped with mini-GF was achieved with a dedicated two-dimensional unsteady CFD model, by applying a ramp-up motion to the airfoil in the desired AoA range [11]. Ramp-up speed Ω was selected in such a way that the airfoil reduced frequency k=Ωc/(2u) ≤ 0.001, to avoid dynamic effects.…”

Section: Cfd Airfoil Simulationsmentioning

confidence: 99%

“…Ramp-up speed Ω was selected in such a way that the airfoil reduced frequency k=Ωc/(2u) ≤ 0.001, to avoid dynamic effects. Although computationally more expensive, the unsteady formulation was in fact required by the MGF, which -especially at the lower AoA -is characterized by a high-frequency vortex shedding [11]. The ANSYS ® FLUENT ® (v. 20.2) solver, based on a combination of the consolidated numerical approaches developed for GF [11] and LE erosion [2] simulations is used.…”

Section: Cfd Airfoil Simulationsmentioning

confidence: 99%

“…Although computationally more expensive, the unsteady formulation was in fact required by the MGF, which -especially at the lower AoA -is characterized by a high-frequency vortex shedding [11]. The ANSYS ® FLUENT ® (v. 20.2) solver, based on a combination of the consolidated numerical approaches developed for GF [11] and LE erosion [2] simulations is used. The coupled algorithm for pressure-velocity coupling, the 2 nd order upwind scheme for both RANS and turbulence equations and the second order bounded scheme for time marching were used.…”

Section: Cfd Airfoil Simulationsmentioning

confidence: 99%

“…It must be noted how this feature also limited the simulation timestep, which was selected to comply with both the GF shedding frequency and the airfoil ramp-up one. The overall mesh sizing is determined based on previous studies by the authors where CFD simulations of airfoils with GFs and leading-edge erosion were performed [2,11,14], however the number of elements along the blade surface was conservatively increased to 1000 in order to have sufficient resolution at both leading and trailing edge.…”

Section: Cfd Airfoil Simulationsmentioning

confidence: 99%

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Potential of Mini Gurney Flaps as a Retrofit to Mitigate the Performance Degradation of Wind Turbine Blades Induced by Erosion

Papi

Melani

Alber

et al. 2022

J. Phys.: Conf. Ser.

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Leading edge erosion of wind turbine blades is still an important challenge for wind energy professionals, both at research and industrial level. While the efficiency and durability of materials and coatings are improving rapidly, it is important to explore innovative solutions at the aerodynamic design level to mitigate the adverse effects of surface erosion. For that, a preliminary analysis on the use of Mini Gurney Flaps (MGFs) is presented in the study. High-fidelity Computational Fluid Dynamic (CFD) simulations are used to evaluate the impact of severe leading edge (LE) erosion on the performance of the FFAW3-241 airfoil on the rotor blade of the DTU 10-MW Reference Wind Turbine, which is used as test case. CFD lift and drag polars of the eroded airfoil show that MGFs are able to partially recover aerodynamic efficiency caused by erosion; this suggested evaluating their use as a retrofit solution for blades that already experienced leading edge erosion damage. When tested on the DTU 10MW RWT blade, results show how, if sized correctly, MGFs perform as predicted: the lift curve is shifted back to its design value and performance is improved with respect to the eroded blade. Moreover, as one would expect, higher than optimal MGFs resulted in excessive lift increases and thus decreased performance, even in the case of LE-erosion. Although these devices behave as intended however, based on the results of this paper, performance decreases are noted at high tip-speed-ratios (TSR), due to the blade operating in off-design conditions.

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Section: Cfd Airfoil Simulationsmentioning

confidence: 99%

Section: Cfd Airfoil Simulationsmentioning

confidence: 99%

Section: Cfd Airfoil Simulationsmentioning

confidence: 99%

Section: Cfd Airfoil Simulationsmentioning

confidence: 99%

See 2 more Smart Citations

Potential of Mini Gurney Flaps as a Retrofit to Mitigate the Performance Degradation of Wind Turbine Blades Induced by Erosion

Papi

Melani

Alber

et al. 2022

J. Phys.: Conf. Ser.

Self Cite

View full text Add to dashboard Cite

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“…The latter was simulated for a chord-based Reynolds number of Rec=550x10 3 and angle of attack α=6°, via a blade-resolved and an ALM approach. Numerical set-up is the same for both cases and is based on a consolidated numerical approach developed by some of the authors for airfoil simulation [15]. More in detail, steady Reynolds-Averaged Navier-Stokes (RANS) CFD simulations were carried out with the ANSYS ® Fluent ® (v. 20.2) solver, making use of the k-ω SST turbulence model, the coupled algorithm for pressure-velocity coupling, and the 2 nd order upwind scheme for both RANS and turbulence equations.…”

Section: Finite Wing Simulationsmentioning

confidence: 99%

Simulating tip effects in vertical-axis wind turbines with the actuator line method

Melani

Balduzzi

Bianchini

2022

J. Phys.: Conf. Ser.

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Simulation of the complex, unsteady aerodynamics characterizing Darrieus rotors requires computational tools with a fidelity higher than the ubiquitous Blade Element Momentum (BEM) theory. Among them, the Actuator Line Method (ALM) stands out in terms of accuracy and computational cost. This approach, however, still fails to resolve the vortex-like structures shed at the blade ends, overestimating turbine performance at the higher rotational speeds. Moving from this background, in this study a comprehensive investigation on the ALM’s capability to simulate tip effects and their impact on rotor performance is carried out. To this end, the ALM tool developed by the authors in the ANSYS® FLUENT® environment (v. 20.2) and specifically tailored to the simulation of vertical-axis machines was employed. Both a steady finite wing and a fictitious one-blade Darrieus H-rotor, for which high-fidelity blade-resolved CFD data are available as benchmark, were considered as test cases. ALM simulations were first performed without any correction for different cell sizes and force projection radii, so that the limits of the original approach could be assessed. Then, two different sub-models were applied: the classical semi-empirical Glauert correction and a new methodology based on the Lifting Line Theory (LLT), which was recently proposed by Dağ and Sørensen (DS). The latter was here adapted to vertical-axis machines. Eventually, the blade spanwise load profiles coming from the three approaches were assessed and compared, proving the superior performance of the DS model.

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A review on the use of passive flow control devices as performance enhancement of lift‐type vertical axis wind turbines

Syawitri

Yao

et al. 2022

WIREs Energy & Environment

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This article provides a comprehensive review about passive flow control devices (PFCDs) implemented in lift‐type vertical axis wind turbine (LVAWT), focusing on the underlying flow physics mechanisms and to what extents they can improve the LVAWT performance. In addition, some novel concepts that can be potentially implemented in future are also presented. Based on literature review, it is observed that PFCDs can enhance the power generation of LVAWT up to 172.73% compared with a clean LVAWT. However, this significant improvement still needs to be evaluated carefully by considering the economic feasibility aspect, because PCFDs can increase the design complexity, weight penalty and manufacturing cost of LVAWT. Furthermore, it is essential to design and evaluate the effectiveness of PFCDs using a full VAWT configuration by considering the blade rotating effects and blade‐to‐blade interactions. Finally, evaluation of PFCDs needs to be performed at all ranges of tip speed ratios (TSRs) operation conditions, as there are clear evidences on the correlation between LVAWT performance and different range of TSRs. This article is categorized under: Sustainable Energy > Wind Energy

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Combined Numerical and Experimental Study on the Use of Gurney Flaps for the Performance Enhancement of NACA0021 Airfoil in Static and Dynamic Conditions

Cited by 5 publications

References 0 publications

Potential of Mini Gurney Flaps as a Retrofit to Mitigate the Performance Degradation of Wind Turbine Blades Induced by Erosion

Potential of Mini Gurney Flaps as a Retrofit to Mitigate the Performance Degradation of Wind Turbine Blades Induced by Erosion

Simulating tip effects in vertical-axis wind turbines with the actuator line method

A review on the use of passive flow control devices as performance enhancement of lift‐type vertical axis wind turbines

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