RANS Computations of Wind Turbine Near-Wake Aerodynamics in Uniform and Yawed Inflow

Tsalicoglou, Christina; Jafari, S.; Chokani, Ndaona; Abhari, Reza S.

doi:10.1115/gt2013-96034

Cited by 3 publications

(5 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Sezer‐Uzol et al performed inviscid and a large eddy simulation yawed wind flow analyses of the NREL Phase VI wind turbine, obtaining a good agreement between measurements and simulations for the sectional pressure coefficient distributions. Tsalicoglou et al conducted yawed flow CFD analyses of the MEXICO wind turbine and reported a good agreement between their NS CFD and experimental data. Yu et al studied the yawed rotor flow of the NREL Phase VI turbine using overset grid NS CFD simulations and a zonal laminar‐to‐turbulent transition model.…”

Section: Introductionmentioning

confidence: 99%

Harmonic balance Navier‐Stokes aerodynamic analysis of horizontal axis wind turbines in yawed wind

2018

View full text Add to dashboard Cite

Multimegawatt horizontal axis wind turbines often operate in yawed wind transients, in which the resulting periodic loads acting on blades, drive-train, tower, and foundation adversely impact on fatigue life. Accurately predicting yawed wind turbine aerodynamics and resulting structural loads can be challenging and would require the use of computationally expensive high-fidelity unsteady Navier-Stokes computational fluid dynamics. The high computational cost of this approach can be significantly reduced by using a frequency-domain framework. The paper summarizes the main features of the COSA harmonic balance Navier-Stokes solver for the analysis of open rotor periodic flows, presents initial validation results on the basis of the analysis of the NREL Phase VI experiment, and it also provides a sample application to the analysis of a multimegawatt turbine in yawed wind. The reported analyses indicate that the harmonic balance solver determines the considered periodic flows from 30 to 50 times faster than the conventional time-domain approach with negligible accuracy penalty to the latter. KEYWORDS harmonic balance Navier-Stokes equations, horizontal axis wind turbine aerodynamics, NREL Phase VI wind turbine, NREL 5 MW wind turbine, yawed wind aerodynamics 1 INTRODUCTION Wind energy is a key low-carbon energy source, playing a crucial role in lowering global greenhouse gas emissions, and it is now viewed as one of the most cost-effective climate change mitigation technologies. Current utility-scale horizontal axis wind turbines (HAWTs) already feature fairly high aerodynamic efficiencies; however, because of the spatial and temporal variability of the environmental conditions, HAWTs often experience unsteady flow conditions, which induce fatigue and lower the energy harvest. Several of such regimes can be viewed as periodic, and typical examples include the blades rotating (a) through stratifications of the atmosphere associated with the atmospheric boundary layer, with the wind velocity varying by as much as 6 m/s over a 100-m rotor diameter, 1 (b) through the variable pressure field due to the downwind tower, and (c) in yawed wind, occurring when the freestream wind velocity is no longer orthogonal to the turbine rotor. 2 In all these cases, the fundamental frequency of the periodic excitation is a multiple of the rotor speed.Regarding yawed wind, utility-scale HAWTs typically feature yaw control systems that monitor the wind direction and turn the entire nacelle to realign wind and rotor normal. 2 Yaw actuators, however, adjust the nacelle position after a relatively long time interval from the yaw misalignment detection, and thus, fatigue due to yaw misalignment can be significant. The yawed wind condition also reduces the power produced by the turbine, and the reduction increases nonlinearly with the cosine of the yaw misalignment. Above certain wind speed-and turbine-dependent yaw misalignment thresholds, dynamic stall also occurs, and this aggravates further unsteady loads because of hysteretic force and mom...

show abstract

Section: Introductionmentioning

confidence: 99%

Harmonic balance Navier‐Stokes aerodynamic analysis of horizontal axis wind turbines in yawed wind

2018

View full text Add to dashboard Cite

show abstract

“…Wind turbine operation generates wakes characterized by lowered momentum and enlarged turbulence levels downstream from the turbine. Such phenomena is induced by extraction of kinetic energy from the atmospheric flow, resulting in reduced mean velocity, and increased turbulence regions that are propagated downstream to the next wind turbine generator (WTG) (Kim et al, 2015;Mo et al, 2013;Tsalicoglou, 2012). The development and propagation of these recirculation regions can affect power output and increase the loading of downstream wind turbines in a wind farm.…”

Section: Introductionmentioning

confidence: 99%

Comparisons of wake models profiles with LiDAR data measured downstream from an operating onshore wind turbine

Stival

Andrade

2021

Wind Engineering

View full text Add to dashboard Cite

This study analyzes the performance of Park, Frandsen, and Larsen models to simulate wake development downstream from a wind turbine for freestream wind velocities ranging from 5 to 10 m/s. Analyses are performed in terms of normalized freestream velocity recovery for a longitudinal centerline downstream from the turbine and normalized wind velocity profiles for cross-sections located 500 and 700 m downstream from the wind turbine. Simulated results are compared with high resolution LiDAR data measured during operation of a North American wind farm. Comparisons of longitudinal profiles demonstrate that Larsen and Frandsen models provide the best agreement with measured data for the case of 5 m/s freestream wind velocity, whereas Park model performs best for the 6–9 m/s freestream wind velocity bins. Post-processing of measured data indicates asymmetry of wake profiles at the selected cross-sections. At these locations, Larsen model accurately predicts the west side of normalized velocity profiles, whereas Park and Frandsen models only predict the velocity recovery at the wake centerline.

show abstract

“…Under these conditions, highly unsteady flow conditions over the wind turbine blades is introduced due to a parallel velocity component to the rotor disk. This unsteadiness results from strong radial flow along the span-wise as well as dynamic stall on the blade and also leading edge separation bubbles [1]. As a result, the rotor performance is strongly affected due to the blade load fluctuations which will also affect the operational life of the wind turbine.…”

Section: Introductionmentioning

confidence: 99%

“…The k-ω model has been successfully used to simulate the flow over airfoils and wind turbines. Moreover, it has been used in many wind-turbine CFD studies such as [1], [3] and [14]. All simulations were performed on the Cray XE6 (HLRS) named HORNET using 448 cores …”

Section: Computational Domainmentioning

confidence: 99%

“…These methods vary in their degree of complexity and accuracy ranging from Blade Element Momentum theory (BEM) and lifting line theory [2] to the solution of Navier-Stokes equations using Computational Fluid Dynamics (CFD). Simplified methods such as the lifting line theory were used in [1] and [2] to investigate the aerodynamic loads of the wind turbine under yaw conditions. Simulations for yaw angles of 10 • , 30 • and 60 • were performed at a wind speed of 10 m/sec.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

3-D Time-Accurate CFD Simulations of a Multi-Megawatt Slender Bladed HAWT under Yawed Inflow Conditions

Sayed

Lutz

Krämer

2016

J. Phys.: Conf. Ser.

View full text Add to dashboard Cite

RANS Computations of Wind Turbine Near-Wake Aerodynamics in Uniform and Yawed Inflow

Cited by 3 publications

References 0 publications

Harmonic balance Navier‐Stokes aerodynamic analysis of horizontal axis wind turbines in yawed wind

Harmonic balance Navier‐Stokes aerodynamic analysis of horizontal axis wind turbines in yawed wind

Comparisons of wake models profiles with LiDAR data measured downstream from an operating onshore wind turbine

3-D Time-Accurate CFD Simulations of a Multi-Megawatt Slender Bladed HAWT under Yawed Inflow Conditions

Contact Info

Product

Resources

About