Development of an aeroelastic code based on three‐dimensional viscous–inviscid method for wind turbine computations

Sessarego, Matias; Ramos‐García, Néstor; Sørensen, Jens Nørkær; Shen, Wen Zhong

doi:10.1002/we.2085

Cited by 20 publications

(25 citation statements)

References 39 publications

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“…In this section, the results of the test cases will be shown and validated against DTU's MIRAS-FLEX results as well as FLEX5-Q 3 UIC and FAST codes [11]. DTU's MIRAS-FLEX is a coupled aeroelastic code that is based on a three-dimensional viscous-inviscid method for wind turbine computations.…”

Section: Resultsmentioning

confidence: 99%

“…DTU's MIRAS-FLEX is a coupled aeroelastic code that is based on a three-dimensional viscous-inviscid method for wind turbine computations. The case study for this work is based on the test case #2 of Sessarego et al [11]. The inflow is steady and uniform wind tested at speeds of 10 m/s and 14 m/s.…”

Section: Resultsmentioning

confidence: 99%

“…The pitch regulations had been discarded at the rated power, since it was more interesting to observe the stall behavior of MIRAS-FLEX and its comparison to FLEX5 and FAST as explained in detail by Matias et al [11]. Furthermore, zero values were assigned to the tower shadow, tilt angle and gravity to achieve non-oscillating loads [11]. The solver is applied using k-ω SST model to account for the turbulence effects.…”

Section: Resultsmentioning

confidence: 99%

“…The blade characteristic geometry data was based on previous literature data from Bazilevs et al [10] and Sessarego et al [11]. Firstly, the pressure loads on the blade surface were computed using Ansys Fluent then passed on to Ansys Mechanical to compute the stresses and deformations on the blade.…”

Section: Methodsmentioning

confidence: 99%

“…The computations were run on the Kyushu University multi-core Linux cluster server using the public domain openMPI implementation of the standard message passing interface (MPI). Afterwards, the solver results were validated against the Technical University of Denmark's (DTU) MIRAS-FLEX [11] aeroelastic code results as well as the widely used FLEX5-Q 3 UIC [12] and FAST [13] codes in different cases. …”

Section: Introductionmentioning

confidence: 99%

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Numerical Fluid-Structure Interaction Study on the NREL 5MW HAWT

Halawa

Sessarego

Shen

et al. 2018

J. Phys.: Conf. Ser.

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Abstract. The development of reliable Fluid-Structure Interaction (FSI) simulation tools and models for the wind turbines is a critical step in the design procedure towards achieving optimized large wind turbine structures. Such approach will mitigate the aeroelastic instabilities like: torsional flutter, stall flutter and edgewise instability that introduce extra stresses to the turbine structure leading to reduced life time and substantial failures. In this study, FSI simulations were held using the commercial package Ansys v18.2 solvers as a preliminary step towards our on-going development of a reliable Open-Source solver. These simulations were applied to the full-scale rotor blades of the NREL 5MW reference horizontal axis wind turbine. The aerodynamic loads and structural responses computations were carried out using a steady-state FSI analysis. The computations were run on the Kyushu University multicore Linux cluster using the public domain openMPI implementation of the standard message passing interface (MPI). Finally, the results were validated against the Technical University of Denmark's (DTU) MIRAS aeroelastic code results as well as the widely used FLEX5-Q 3 UIC and FAST codes in different cases showing reasonable agreement. IntroductionThe increased potential for the extraction of wind energy has led to a considerable development in the wind turbines designs. The turbine blades are getting larger and thus introducing new load effects. The flexibility of large wind turbines yields an interaction between the fluid flow and the internal structure loading causing what is known as Fluid-Structure Interaction (FSI) or aeroelastic effects. The consequences of these effects are many instability problems like torsional flutter, stall flutter and edgewise instability imposing extra stresses on the blade structure through fatigue loads that potentially end up to wind turbine failures. Hence, developing reliable FSI simulation tools and models for the blades of wind turbines is a critical step towards developing and optimizing the large wind turbines designs. Many recent studies are centered around the FSI development. Hsu and Bazilevs [1] simulated a full scale turbine using a fully coupled 3D FSI approach by a low order FEM-based ALE-VMS technique. Rafiee et al.[2] investigated the aeroelastic behavior using modified BEM and CFD then constructed an iterative FSI approach. Wang et al. [3] established an FSI model using CFD and FEA with one-way coupling interface between them. Carrión et al.[4] applied a CFD-CSD method to perform aeroelastic

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Numerical Fluid-Structure Interaction Study on the NREL 5MW HAWT

Halawa

Sessarego

Shen

et al. 2018

J. Phys.: Conf. Ser.

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Hybrid vortex simulations of wind turbines using a three‐dimensional viscous–inviscid panel method

et al. 2017

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A hybrid filament‐mesh vortex method is proposed and validated to predict the aerodynamic performance of wind turbine rotors and to simulate the resulting wake. Its novelty consists of using a hybrid method to accurately simulate the wake downstream of the wind turbine while reducing the computational time used by the method. The proposed method uses a hybrid approach, where the near wake is resolved by using vortex filaments, which carry the vorticity shed by the trailing edge of the blades. The interaction of the vortex filaments in the near vicinity of the wind turbine is evaluated using a direct calculation, whereas the contribution from the large downstream wake is calculated using a mesh‐based method. The hybrid method is first validated in detail against the well‐known MEXICO experiment, using the direct filament method as a comparison. The second part of the validation includes a study of the influence of the time‐integration scheme used for evolving the wake in time, aeroelastic simulations of the National Renewable Energy Laboratory 5 MW wind turbine and an analysis of the central processing unit time showing the gains of using the hybrid filament‐mesh method. Copyright © 2017 John Wiley & Sons, Ltd.

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Vortex simulations of wind turbines operating in atmospheric conditions using a prescribed velocity‐vorticity boundary layer model

et al. 2018

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A prescribed velocity-vorticity boundary layer model for the vorticity transport equation is proposed, which corrects the unphysical upward deflection of the wake seen in a simpler prescribed velocity shear approach. A Lagrangian implementation of the boundary layer model has been investigated using our in-house vortex solver MIRAS. The MIRAS code contains both an aerodynamic part and a structural-mechanical part taking into account aeroelastic phenomena. The solver is employed to simulate flows around wind turbines and uses a combination of filaments and particles in order to mimic the vorticity released by the wind turbine blades. The vorticity is interpolated onto a uniform Cartesian mesh, where the interaction is efficiently calculated by an fast Fourier transform-based method. Simulations of wind turbines operating in an atmospheric boundary layer flow are carried out and analysed in detail for a range of scenarios. The manuscript focuses on studying the influence of wind shear and turbulence, which is varied to mimic natural atmospheric conditions. A traverse virtual probe up to 30 diameters downstream of the rotor plane is used to investigate the properties of the turbulent wake flow for the different cases.This includes mean and standard deviation of the streamwise velocity component, wake deficit, Reynolds stresses, and power spectral density of the velocity signal. The results show that combining a prescribed boundary layer approach with a vortex method gives consistent and physically correct results if properly implemented. KEYWORDS aeroelasticity, atmospheric boundary layer, turbulence, vortex method, wind shear, wind turbine INTRODUCTIONVortex methods initially entered the wind energy community as a more physically accurate alternative to the basic Blade Element Momentum method (BEM) technique, which is based on 1-dimensional momentum theory and aimed to be used for rotor design. However, vortex methods have quickly developed in recent years and now can be seen as an advanced and matured tool capable of performing high-fidelity simulations of 1 or more turbines. Vortex methods are not only of interest during the actual rotor design process but also as analysis tool to investigate more complex scenarios, including aeroelastic, turbulent inflow, and shear effects. [1][2][3][4][5][6] Vortex solvers can be combined with different aerodynamic models depending on the degree of complexity required. Enumerated in ascending complexity, they can be classified as lifting line (LL) vortex lattice, potential panel method, and viscous-inviscid panel method. The latter class being the more physically correct, since it resolves the actual geometry of the blade accounting for the viscous effects enclosed inside the boundary layer.The present paper focuses on the lower degree of fidelity in terms of aerodynamic modeling of the wind turbine blades, using the LL approach. With the LL model, the rotor blades are represented by discrete filaments, which account for the bound vortex strength and release vorticity into the ...

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Development of an aeroelastic code based on three‐dimensional viscous–inviscid method for wind turbine computations

Cited by 20 publications

References 39 publications

Numerical Fluid-Structure Interaction Study on the NREL 5MW HAWT

Numerical Fluid-Structure Interaction Study on the NREL 5MW HAWT

Hybrid vortex simulations of wind turbines using a three‐dimensional viscous–inviscid panel method

Vortex simulations of wind turbines operating in atmospheric conditions using a prescribed velocity‐vorticity boundary layer model

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