Large-eddy simulation study of multi-rotor wind turbines

Ghaisas, Niranjan S.; Ghate, Aditya S.; Lele, Sanjiva K.

doi:10.1088/1742-6596/1037/7/072021

Cited by 28 publications

(24 citation statements)

References 14 publications

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“…The power deficit further downstream (wind turbines B3 and B4) is similar in both the SR and MR wind farms (difference is less than 2%). These results are significantly different from Ghasais et al [3], who used LES to show that all downstream MR wind turbines in a row experience between 15-45% smaller power deficits compared to a row of SR wind turbines, for an aligned wind direction. It should be noted that Ghasais et al [3] used an unrealistically large tip clearance of 1D, while we have used a more common tip clearance of 0.05D [17], as depicted in Figure 2.…”

Section: Power Deficitcontrasting

confidence: 96%

“…These results are significantly different from Ghasais et al [3], who used LES to show that all downstream MR wind turbines in a row experience between 15-45% smaller power deficits compared to a row of SR wind turbines, for an aligned wind direction. It should be noted that Ghasais et al [3] used an unrealistically large tip clearance of 1D, while we have used a more common tip clearance of 0.05D [17], as depicted in Figure 2. To investigate the results of Ghasais et al [3], we have performed an additional test case based on LES, as described in Appendix A.…”

Section: Power Deficitcontrasting

confidence: 96%

“…Note that changing the tip clearance from 0.1D to 0.05D has a negligible effect on the results. However, when the tip clearance between the rotors of the MR wind turbine is set to 1D, the difference in power deficit between the SR and MR wind turbine row increases and is still present for the entire row, which explains the LES results of Ghasais et al [3].…”

Section: Power Deficitmentioning

confidence: 94%

“…It should be noted that Ghasais et al [3] used an unrealistically large tip clearance of 1D, while we have used a more common tip clearance of 0.05D [17], as depicted in Figure 2. To investigate the results of Ghasais et al [3], we have performed an additional test case based on LES, as described in Appendix A. Figure 9, shows that the power deficit of a SR and MR wind turbine row is only significantly different for the first downstream wind turbine (using a tip clearance of 0.1D), as also observed in the RANS simulations using a tip clearance of 0.05D.…”

Section: Power Deficitmentioning

confidence: 99%

“…Ghaisas et el. [3] employed large-eddy simulations (LES) to show that a row of five MR wind turbines with an inter spacing of 4D eq has a reduced power deficit compared to a row of equivalent SR wind turbines when the wind direction is aligned with the row orientation. In this work, the benefit of MR wind turbines in wind farms is further investigated in terms of AEP using RANS simulations of 4 × 4 10 MW wind turbines for three inter spacings: 3, 4 and 5D eq .…”

Section: Introductionmentioning

confidence: 99%

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Improved energy production of multi-rotor wind farms

Laan

Abkar

2019

J. Phys.: Conf. Ser.

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The multi-rotor (MR) wind turbine concept can be used to upscale wind turbines without increasing the rotor diameter, which can be beneficial for transport, manufacture and design of wind turbines blades. The rotor interaction of a MR wind turbine leads to a faster wake recovery compared to an equivalent single-rotor (SR) wind turbine wake. In this article, the benefit of the faster wake recovery of MR wind turbines is quantified using Reynolds-averaged Navier-Stokes simulations of a 4×4 rectangular MR wind farm, for three different inter wind turbine spacings. The simulations predict an increase of 0.3-1.7% in annual energy production for the MR wind farm with respect to an equivalent SR wind farm, where the highest gain is obtained for the tightest inter wind turbine spacing. The gain in AEP is mainly caused by the aligned wind directions for the first downstream wind turbine in a wind turbine row of the MR wind farm, which is verified by an additional large-eddy simulation. arXiv:1907.07012v1 [physics.flu-dyn]

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Section: Power Deficitcontrasting

confidence: 96%

Section: Power Deficitcontrasting

confidence: 96%

Section: Power Deficitmentioning

confidence: 94%

Section: Power Deficitmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Improved energy production of multi-rotor wind farms

Laan

Abkar

2019

J. Phys.: Conf. Ser.

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Wake steering of multirotor wind turbines

et al. 2021

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In this paper, wake steering is applied to multirotor turbines to determine whether it has the potential to reduce wind plant wake losses. Through application of rotor yaw to multirotor turbines, a new degree of freedom is introduced to wind farm control such that wakes can be expanded, channelled or redirected to improve inflow conditions for downstream turbines. Five different yaw configurations are investigated (including a baseline case) by employing large‐eddy simulations (LES) to generate a detailed representation of the velocity field downwind of a multirotor wind turbine. Two lower‐fidelity models from single‐rotor yaw studies (curled‐wake model and analytical Gaussian wake model) are extended to the multirotor case, and their results are compared with the LES data. For each model, the wake is analysed primarily by examining wake cross‐sections at different downwind distances. Further quantitative analysis is carried out through characterisations of wake centroids and widths over a range of streamwise locations and through a brief analysis of power production. Most significantly, it is shown that rotor yaw can have a considerable impact on both the distribution and magnitude of the wake velocity deficit, leading to power gains for downstream turbines. The lower‐fidelity models show small deviation from the LES results for specific configurations; however, both are able to reasonably capture the wake trends over a large streamwise range.

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Aeroelastic load analysis of a co‐rotating quad‐rotor wind turbine

Ferede

Gandhi

2021

Wind Energy

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An aeroelastic analysis is carried out to assess the loads on a selected quad‐rotor wind turbine vis‐à‐vis those on an equivalent rated single‐rotor turbine, with a specific focus on a comparison of support structure loads (e.g., tower root, yaw‐bearing, and boom loads). A quad‐rotor wind turbine with combined rated power of 6 MW and a single‐rotor with equivalent machine rating are modeled in SIMAPCK coupled with AerodynV15 (including turbulent wind input from TurbSim) to calculate the aerodynamic loads. A correction for tower/boom shadow is implemented in Matlab to account for reduction in (axial) incoming wind due to the presence of support structures that carry the rotors. The performance of the quad‐rotor wind turbine, with the single‐rotor as baseline, is carried out for load cases selected from wind turbine certification standard (IEC‐61400‐1) covering the following: nominal loads under normal wind speed profile, fatigue loads under normal turbulence, and ultimate loads under extreme turbulence. Results show that, comparing the quad‐rotor tower root loads to those of the single‐rotor turbine under extreme turbulence, the side‐side force is up to 31% higher, the force‐aft bending moment is up to 15% higher, and the normal force is up to 46% higher due to additional boom/nacelle inertial loads.

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Large-eddy simulation study of multi-rotor wind turbines

Cited by 28 publications

References 14 publications

Improved energy production of multi-rotor wind farms

Improved energy production of multi-rotor wind farms

Wake steering of multirotor wind turbines

Aeroelastic load analysis of a co‐rotating quad‐rotor wind turbine

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