Experimental verification of computational predictions in power generation variation with layout of offshore wind farms

Theunissen, Raf; Housley, Paul; Allen, Christian B; Carey, Charles

doi:10.1002/we.1788

Cited by 23 publications

(27 citation statements)

References 61 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Previous experiments [15] with the experimental setup used in this study show that the mean surrogate power reaches an approximate plateau for both the aligned and staggered layout around the seventeenth row. To fit a scaled farm with twenty rows in a wind tunnel test-section with a typical length on the order of 5 − 10 m, the scaled turbine model must have a diameter as small as D = 0.025 − 0.07 m. The design challenges of scaling turbines for wind tunnel studies of large farms have motivated the development of static porous disk models [15,32,33,40], in analogy to the numerical approach of actuator disk models in LES [10,41]. Porous disk models are designed to exert the same integral thrust force on the flow, and to create an equivalent turbulent wake by mimicking the flow-through behavior of a wind turbine rotor.…”

Section: A Porous Disk Modelingmentioning

confidence: 99%

“…Therefore, an estimate for turbine performance must be obtained in an indirect way. Initially, studies focused on measurements of the velocity field [32], or the integral drag force of the entire scaled farm [33]. More recently, Bossuyt et al [15] instrumented individual porous disk models with strain gages, to measure the instantaneous integral thrust force.…”

Section: A Porous Disk Modelingmentioning

confidence: 99%

See 1 more Smart Citation

Effect of layout on asymptotic boundary layer regime in deep wind farms

2018

View full text Add to dashboard Cite

The power output of wind farms depends strongly on spatial turbine arrangement, and the resulting turbulent interactions with the atmospheric boundary layer. Wind farm layout optimization to maximize power output has matured for small clusters of turbines, with the help of analytical wake models. On the other hand, for large farms approaching a fully-developed regime in which the integral power extraction by turbines is balanced through downwards transport of mean kinetic energy, the influence of turbine layout is much less understood. The main goal of this work is to study the effect of turbine layout on the power output for large wind farms approaching a fullydeveloped regime. For this purpose we employ an experimental setup of a scaled wind farm with one-hundred porous disk models, of which sixty are instrumented with strain gages. Our experiments cover a parametric space of fifty-six different layouts for which the turbine-area-density is constant, focusing on different turbine arrangements including non-uniform spacings. The straingage measurements are used to deduce surrogate power and unsteady loading on turbines for each layout. Our results indicate that the power asymptote at the end of the wind farm depends on the layout in different ways. Firstly, for layouts with a relatively uniform spacing we find that the power asymptote in the fully developed regime reaches approximately the same value, similarly to the prediction of available analytical models. Secondly, we show that the power asymptote in the fully-developed regime can be lowered by inefficient turbine placement, for instance when a large number of the turbines are located in the near wake of upstream turbines. Thirdly, our experiments indicate that an uneven spacing between turbines can improve the overall power output for both the developing and fully-developed part of large wind farms. Specifically, we find a higher power asymptote for a turbine layout with a significant streamwise uneven spacing (i.e. a large streamwise spacing between pairs of closely spaced rows that are slightly staggered). Our results thereby indicate that such a layout may promote beneficial flow interactions in the fully-developed regime for conditions with a strongly prevailing wind direction.Wind turbines are clustered in farms to provide the largest possible cumulative power, within available surface and cost. Inevitably, when turbines are closely spaced together, the momentum deficit in wakes from upstream turbines reduces the available power for downstream ones, while increased turbulence levels result in higher unsteady loading of turbine components. Depending on turbine location, operational control, and inflow conditions, wake induced power losses can be as high as 50%, compared to a lone standing turbine [1].An important aspect for wind farm design is therefore to better understand the relation between turbine layout, and the resulting wake losses and structural loading.Analytical wake models that describe downstream advection and expansion of turbine wakes [2...

show abstract

Section: A Porous Disk Modelingmentioning

confidence: 99%

Section: A Porous Disk Modelingmentioning

confidence: 99%

Effect of layout on asymptotic boundary layer regime in deep wind farms

2018

View full text Add to dashboard Cite

show abstract

“…The power output characteristics of a 3‐turbine array were measured by Annoni et al to analyze the effect of individual turbine control on wind farm dynamics. Theunissen et al performed a systematic study on turbine wake characteristics and variations in power generation with turbine layout for an 80 turbine wind farm. More recently, Bossuyt et al conducted wind tunnel experiments to study the unsteady loading and spatial‐temporal characteristics of power outputs of a wind farm model represented by using 100 porous disk models.…”

Section: Introductionmentioning

confidence: 99%

An experimental investigation on the wake interferences among wind turbines sited in aligned and staggered wind farms

Tian

Ozbay

2017

Wind Energy

View full text Add to dashboard Cite

show abstract

“…Two different approaches for blade meshing were implemented: unstructured tetrahedral and unstructured hexahedral. Theunissen et al [19] developed a computational and experimental study to optimize the layout of an offshore wind farm array with 80 turbines. Tran et al [20] developed an unsteady CFD model for a floating offshore, using the software FAST (Fatigue, Aerodynamics, Structure and Turbulence) and Unsteady BEM equations for the analysis.…”

Section: Nrel 5 Mwmentioning

confidence: 99%

Development of a Computational System to Improve Wind Farm Layout, Part II: Wind Turbine Wakes Interaction

Rodrigues

Lengsfeld

2019

Energies

View full text Add to dashboard Cite

The second part of this work describes a wind turbine Computational Fluid Dynamics (CFD) simulation capable of modeling wake effects. The work is intended to establish a computational framework from which to investigate wind farm layout. Following the first part of this work that described the near wake flow field, the physical domain of the validated model in the near wake was adapted and extended to include the far wake. Additionally, the numerical approach implemented allowed to efficiently model the effects of the wake interaction between rows in a wind farm with reduced computational costs. The influence of some wind farm design parameters on the wake development was assessed: Tip Speed Ratio (TSR), free-stream velocity, and pitch angle. The results showed that the velocity and turbulence intensity profiles in the far wake are dependent on the TSR. The wake profile did not present significant sensitivity to the pitch angle for values kept close to the designed condition. The capability of the proposed CFD model showed to be consistent when compared with field data and kinematical models results, presenting similar ranges of wake deficit. In conclusion, the computational models proposed in this work can be used to improve wind farm layout considering wake effects.

show abstract

Experimental verification of computational predictions in power generation variation with layout of offshore wind farms

Cited by 23 publications

References 61 publications

Effect of layout on asymptotic boundary layer regime in deep wind farms

Effect of layout on asymptotic boundary layer regime in deep wind farms

An experimental investigation on the wake interferences among wind turbines sited in aligned and staggered wind farms

Development of a Computational System to Improve Wind Farm Layout, Part II: Wind Turbine Wakes Interaction

Contact Info

Product

Resources

About