Wake Modeling with the Actuator Disc Concept

Crasto, Giorgio; Gravdahl, Arne; Castellani, Francesco; Piccioni, Emanuele

doi:10.1016/j.egypro.2012.06.122

Cited by 50 publications

(27 citation statements)

References 1 publication

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“…The associated pressure drop ( ) ∆p is calculated from a semi-empirical relation between the thrust coefficient curve and the velocity at the disc. While these simulations provide a good estimate for the far wake velocity profiles, the flow behavior in front of the AD and in the near wake is not captured accurately [12]. The discrepancies between computed velocity profiles and real measurements may be attributed to the way the∆p is distributed over several cells.…”

Section: Introductionmentioning

confidence: 98%

“…The influence of AD in the equations can be implemented as an additional body force acting against the flow. The most common approach reported in the literature is to create an interface where a momentum sink term is applied [12,13]. The associated pressure drop ( ) ∆p is calculated from a semi-empirical relation between the thrust coefficient curve and the velocity at the disc.…”

Section: Introductionmentioning

confidence: 99%

“…The discrepancies between computed velocity profiles and real measurements may be attributed to the way the∆p is distributed over several cells. Numerically, the force is smeared over the neighboring cells affecting the flow in the local position of the AD [12].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Computational study of diffuser augmented wind turbine using actuator disc force method

Dighe¹,

Avallone²,

Bussel³

2016

Int. J. CMEM

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In this paper, a computational approach, based on the solution of Reynolds-averaged-Navier-Stokes (RANS) equations, to describe the flow within and around a diffuser augmented wind turbine (DAWT) is reported. In order to reduce the computational cost, the turbine is modeled as an actuator disc (AD) that imposes a resistance to the passage of the flow. The effect of the AD is modeled applying two body forces, upstream and downstream of the AD, such that they impose a desired pressure jump. Comparison with experiments carried out in similar conditions shows a good agreement suggesting that the adopted methodology is able to carefully reproduce real flow features.

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Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Computational study of diffuser augmented wind turbine using actuator disc force method

Dighe¹,

Avallone²,

Bussel³

2016

Int. J. CMEM

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show abstract

“…The under-prediction of the far wake by ADM was observed also by other studies (Rados et al, 2012;Sanderse et al, 2011;Vafiadis et al, 2013;Crasto et al, 2012;Prospathopoulos et al, 2011). Especially for the downstream distance of five diameters, which is of high interest since it is commonly used by industry as a separation distance in wind farms, results show that there is a failure to capture accurately the velocity deficit with the standard actuator disk model for most turbulence models.…”

mentioning

confidence: 56%

“…Once the U ref is known, C T can be estimated through the thrust curve of the wind turbine generator considered as uniform 15 over the rotor area (Rados et al, 2012;Crasto et al, 2012;Mikkelsen, 2003). However, in operating conditions, the flow across the rotor is very complex with varying span-wise properties, due to the blade characteristics, rotational velocity, turbulence, finite number of blades and also other flow characteristics related to non-uniform inflow conditions, atmospheric boundary layer shear and so on.…”

Section: Wind Turbine Modellingmentioning

confidence: 99%

Full HAWT rotor CFD simulations using different RANS turbulence models compared with actuator disk and experimental measurements

Stergiannis

Beeck

Runacres

2017

Preprint

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Abstract.The development of large-scale wind energy projects has created the demand for increasingly accurate and efficient models that limit a project's uncertainties and risk. Wake effects are of great importance and are relevant for the optimization of wind farms. Despite a growing body of research, there are still many open questions and challenges to overcome. In computational modelling, there are always numerous input parameters such as material properties, geometry, boundary conditions, initial 5 conditions, turbulence modelling etc. whose estimation is difficult and their values are often inaccurate or uncertain. Due to the lack of information of several sources, e.g., uncertainties present in operating conditions as well as in the mathematical modelling, the computational output is also uncertain. It is therefore very important to validate the mathematical models with experiments performed in controlled conditions. In the present paper, the single wake characteristics of a Horizontal-Axis Wind Turbine Rotor (HAWT) and their spatial evolution are investigated with different Computational Fluid Dynamics (CFD) Numerical results are compared with experimental data along three horizontal lines downstream, covering all the wake regions. Wake predictions are shown to be very sensitive to the choice of the RANS turbulence model. For most cases, the ADM under-predicts the velocity deficit, except for the case of RNG k-ε which showed a superb performance in the mid and far wake. The full wind turbine rotor simulations showed good agreement to the experimental data, mainly in the near wake, 20 amplifying the differences between the simplified models.

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Experimental and numerical investigations of actuator disks for wind turbines

Ranjbar

Kia

Nasrazadani

et al. 2020

Energy Science & Engineering

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The expenses of a wind turbine modeling in particular a wind farm modeling either numerically or experimentally cause to take the advantages of actuator disks (AD). Porous disks (PD) are used to simulate actuator disks in experiments especially for wake studies. A rotor of a wind turbine replaced by a PD can be modeled efficiently with less cost and process time. For a proper PD selection, some semi‐empirical equations are suggested for a range of solidity of 0.2‐0.6. These equations came from a number of tests. The PDs with different dimensions and solidity values were considered for the tests and models. The results of 2D and 3D numerical simulations and the experimental results show that at the solidity of 0.5, the coefficient of performance of a PD reaches approximately 16/27 which is equal to the Betz's limit; the relation between the coefficient of power and the solidity is fitted by a parabolic equation. The average error of the proposed equations for the power coefficient is reported 1.59%. Finally, based on the current results, some semi‐empirical equations are suggested to help the initial PD selection, and then, the cost of further studies may decrease.

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Wake Modeling with the Actuator Disc Concept

Cited by 50 publications

References 1 publication

Computational study of diffuser augmented wind turbine using actuator disc force method

Computational study of diffuser augmented wind turbine using actuator disc force method

Full HAWT rotor CFD simulations using different RANS turbulence models compared with actuator disk and experimental measurements

Experimental and numerical investigations of actuator disks for wind turbines

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