Numerical investigation of wake behind a HAWT using modified actuator disc method

Naderi, Shayan; Torabi, Farschad

doi:10.1016/j.enconman.2017.07.003

Cited by 41 publications

(15 citation statements)

References 28 publications

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“…The analysis also using post processing to examvorticesfor wind speed 9m/s with the Q Criterion [26]method shows the same trend that recovery has begun to occur about x/Dd = 4. This result is compatible withthe single VAWT simulation result which provides wake recovery occurring in the range of x/Dd = 5 [23], and based on experiment, wake recovery from straight-bladed Vertical Axis Wind turbine occurs in the range x/Dd = 3.3 and x/ Dd = 4.5 [4] which much shorter than HAWT wake recovery that happens in x/Dd= 15 [27][28][29].This indicates that with the area of the wind sweep cross-section similar to the HAWT, hybrid VAWT has a higher power density than HAWT. Based on the calculation of Power density its show that for hybrid VAWT produce power density 8.29 W/m2over 300 percent than HAWT.…”

Section: Discussionsupporting

confidence: 89%

The effect of hybrid savonius and darrieus turbine on the change of wake recovery and improvement of wind energy harvesting

Erwin¹,

Surjosatyo²,

Nugroho³

et al. 2018

J Appl Eng Science

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The energy crisis encourages the development of renewable energy; one of the potential renewable energy is wind. In the field of wind turbine there is a two-way development of the utilization of wind energy, first by making a large wind turbine, the second by making a wind farm energy with a relatively small wind turbine.This hybrid VAWT wind turbine (Sultan Wind Turbine) is designed to work optimally on a farm array, on a wind turbine farm array will always cause a wake effect that will reduce overall wind turbine and farm array performance, an investigation with a CFD simulation is required to predict how far the wake effect will be before farm array build.The use of simulation software has been widely used to predict the effects of this wake, and experiments in the laboratory have also been done to predict the effects of a wake as well.This study'spurpose is to predict the distance area of the recovery wake behind the wind turbine, this distance which will be the reference distance between wind turbine units and determining the density of the turbine in a farm. Simulation using Computational Fluid Dynamics (CFD), with a method of Multi Frame Reference (MRF). Analysis using descriptive and inferential method in statistics such as mean, Kolmogorov-Smirnov Z and KruskalWalis test.From the analysis of simulation results and data processing descriptively and analytic statistic, it can be concluded from the data given, the distance of x/D=4, wind speed has recovery to the value near the input speed and no significant change to x/D= 9. Then it can be concluded that the distance between two wind turbines that can be used is a distance of 3.6 meters.These data suggest that the hybrid farm array VAWT savonius and darrieus have a higher power density compared to HAWT. From this power density calculation the hybrid VAWT has a greater electrical potential up to 300 percent compared to the HAWT farm array.

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Section: Discussionsupporting

confidence: 89%

The effect of hybrid savonius and darrieus turbine on the change of wake recovery and improvement of wind energy harvesting

Erwin¹,

Surjosatyo²,

Nugroho³

et al. 2018

J Appl Eng Science

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“…With the change of wind direction, the turbines in the offshore wind farms are always under either the AL conditions or the unaligned conditions 24,27,28 . The AL conditions are known to cause severe power losses on the downstream turbines with full‐wake effects, whereas the unaligned conditions can bring about an increment in the total frontal area of the downstream turbines with no/partial wake effects to increase power generation.…”

Section: Introductionmentioning

confidence: 99%

Effects of inflow turbulence intensity and turbine arrangements on the power generation efficiency of large wind farms

Lin

Chang

2020

Wind Energy

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In this study, we conduct a series of large-eddy simulations (LESs) to study the impact of different incoming turbulent boundary layer flows over large wind farms, with a particular focus on the overall efficiency of electricity production and the evolution of the turbine wake structure. Five representative turbine placements in the large wind farm are considered, including an aligned layout and four staggered layouts with lateral or vertical offset arrangements. Four incoming flow conditions are used and arranged from the LESs of the ABL flow over homogeneous flat surfaces with four different aerodynamic roughness lengths (i.e., z0 = 0.5, 0.1, 0.01, and 0.0001 m), where the hub-height turbulence intensity levels are about 11.1%, 8.9%, 6.8%, and 4.9%, respectively. The simulation results indicate that an enhancement in the inflow turbulence level can effectively increase the power generation efficiency in the large wind farms, with about 23.3% increment on the overall farm power production and up to about 32.0% increment on the downstream turbine power production. Under the same inflow condition, the change of the turbine-array layouts can increase power outputs within the first 10 turbine rows, which has a maximum increment of about 26.5% under the inflow condition with low turbulence. By comparison, the increase of the inflow turbulence intensity facilitates faster wake recovery that raises the power generation efficiency of large wind farms than the adjustment of the turbine placing layouts. K E Y W O R D Slarge eddy simulation, power output, surface roughness, turbulence intensity, wind farm layout

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“…Each approach has its unique benefits and disadvantages. The constant actuator disk method is based on MT [38] and has attractive features: the first is the simplicity of the modelling, stationary rather than non-stationary mesh solution; and the second is the methods confidence [81]. However, the main disadvantage is the lack of swirl in the flow, an important characteristic of the wake formation and recovery.…”

Section: Rotor Thrust Representationmentioning

confidence: 99%

A Review on Numerical Development of Tidal Stream Turbine Performance and Wake Prediction

et al. 2020

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Recently, the output of Computational Fluid Dynamic (CFD) prediction on tidal stream turbine systems has been receiving great attention owing to the vast and untapped tidal stream potential. For several years, many publications have documented the accuracy of CFD methods for steady flows, but not for unsteady flows. A challenging area persisting in the computational field is its dependence on large computing resources, and the unsteady nature of usual tidal streams. To overcome this problem, researchers have proposed modelling simpler, representative devices or combined CFD with alternative predictive methods. Nevertheless, the turbulent modelling has been a critical issue in the CFD methods and great effort has been devoted to the study of turbulence and wave effect on the wake and functioning of the turbine. The present paper is a review of CFD application on tidal stream turbine performance in both steady and unsteady flows. The performance of the turbine predicted by actuator and blade resolved methods, has been in accordance with laboratory observations. Findings of the wake have been both consistent and inconsistent with measurements, arising from interpretation of the blade force, fluid-solving method and onset flow model, and downstream range distance. With regards to arrays, preliminary work shows turbine arrangement can have profound effects in the onset flow, and in consequence, the performance of adjacent turbine rows. The results reported appear to support the wind similarity assumption, such as wake Gaussian velocity distributions and fluctuating turbine output in unsteady flows. Under the influence of surface waves, the wake recovers faster than steady flow condition due to the flow's convective acceleration, but the mean performance stays almost equal. The findings in this paper give a critical review and insight of important implications for future turbine research, such as experimental validation of the turbine prediction output in small and large arrays. INDEX TERMS Computational fluid dynamic, tidal stream turbine, unsteady flow, turbine performance, wake characteristics.

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Numerical investigation of wake behind a HAWT using modified actuator disc method

Cited by 41 publications

References 28 publications

The effect of hybrid savonius and darrieus turbine on the change of wake recovery and improvement of wind energy harvesting

The effect of hybrid savonius and darrieus turbine on the change of wake recovery and improvement of wind energy harvesting

Effects of inflow turbulence intensity and turbine arrangements on the power generation efficiency of large wind farms

A Review on Numerical Development of Tidal Stream Turbine Performance and Wake Prediction

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