Stability of Methods in the Free-Vortex Wake Analysis of Wind Turbines

2004 ◽  
Author(s):  
Sandeep Gupta ◽  
John Leishman
Keyword(s):  
Wind Turbines ◽  
Vortex Wake ◽  
Free Vortex

Accuracy of the aerodynamic performance of wind turbines using vortex core models in the free vortex wake method

2019 ◽  
Vol 11 (5) ◽  
pp. 053307
Author(s):  
Bofeng Xu ◽  
Bingbing Liu ◽  
Xin Cai ◽  
Yue Yuan ◽  
Zhenzhou Zhao ◽  
...  
Keyword(s):  
Wind Turbines ◽  
Vortex Core ◽  
Aerodynamic Performance ◽  
Vortex Wake ◽  
Free Vortex

An Unsteady Aerodynamics Model for Lifting Line Free Vortex Wake Simulations of HAWT and VAWT in QBlade

2016 ◽  
Author(s):  
Juliane Wendler ◽  
David Marten ◽  
George Pechlivanoglou ◽  
Christian Navid Nayeri ◽  
Christian Oliver Paschereit
Keyword(s):  
Wind Turbines ◽  
Turbine Blades ◽  
Unsteady Aerodynamics ◽  
Vortex Method ◽  
Vertical Axis ◽  
Empirical Method ◽  
Vortex Wake ◽  
Simulation Code ◽  
Free Vortex ◽  
Lifting Line

This paper describes the introduction of an unsteady aerodynamics model applicable for horizontal and vertical axis wind turbines (HAWT/VAWT) into the advanced blade design and simulation code QBlade, developed at the HFI of the TU Berlin. The software contains a module based on lifting line theory including a free vortex wake algorithm (LLFVW) which has recently been coupled to the structural solver of FAST to allow for time-resolved aeroelastic simulations of large, flexible wind turbine blades. The aerodynamic model yields an accuracy improvement with respect to Blade Element Momentum (BEM) theory and a more practical approach compared to higher fidelity methods such as Computational Fluid Dynamics (CFD) which are too computationally demanding for load case calculations. To capture the dynamics of flow separation, a semi-empirical method based on the Beddoes-Leishman model now extends the simple table lookups of static polar data by predicting the unsteady lift and drag coefficients from steady data and the current state of motion. The model modifications for wind turbines and the coupling to QBlade’s vortex method are described. A 2D validation of the implementation is presented in this paper to demonstrate the capability and reliability of the resulting simulation scheme. The applicability of the model is shown for exemplary HAWT and VAWT test cases. The modelling of the dynamic stall vortex, the empiric model constants as well as the influence of the dynamic coefficients on performance predictions are investigated.

scholarly journals Comparison of two vortex models of wind turbines using a free vortex wake scheme

2016 ◽  
Vol 753 ◽  
pp. 022059 ◽  
Author(s):  
B F Xu ◽  
Y Yuan ◽  
T G Wang ◽  
Z Z Zhao
Keyword(s):  
Wind Turbines ◽  
Vortex Wake ◽  
Free Vortex

scholarly journals A Simplified Free Vortex Wake Model of Wind Turbines for Axial Steady Conditions

2018 ◽  
Vol 8 (6) ◽  
pp. 866 ◽  
Author(s):  
Bofeng Xu ◽  
Tongguang Wang ◽  
Yue Yuan ◽  
Zhenzhou Zhao ◽  
Haoming Liu
Keyword(s):  
Wind Turbines ◽  
Vortex Wake ◽  
Free Vortex ◽  
Wake Model

scholarly journals Development of a Simulation Tool Coupling Hydrodynamics and Unsteady Aerodynamics to Study Floating Wind Turbines

2017 ◽  
Author(s):  
Vincent Leroy ◽  
Jean-Christophe Gilloteaux ◽  
Maxime Philippe ◽  
Aurélien Babarit ◽  
Pierre Ferrant
Keyword(s):  
Wind Turbines ◽  
Unsteady Aerodynamics ◽  
Offshore Wind ◽  
Computational Time ◽  
Vortex Wake ◽  
Rotor Wake ◽  
Free Vortex ◽  
Code Validation ◽  
Floating Offshore Wind Turbines ◽  
Wake Interactions

Depending on the environmental conditions, floating Horizontal Axis Wind Turbines (FHAWTs) may have a very unsteady behaviour. The wind inflow is unsteady and fluctuating in space and time. The floating platform has six Degrees of Freedom (DoFs) of movement. The aerodynamics of the rotor is subjected to many unsteady phenomena: dynamic inflow, stall, tower shadow and rotor/wake interactions. State-of-the-art aerodynamic models used for the design of wind turbines may not be accurate enough to model such systems at sea. For HAWTs, methods such as Blade Element Momentum (BEM) [1] have been widely used and validated for bottom fixed turbines. However, the motions of a floating system induce unsteady phenomena and interactions with its wake that are not accounted for in BEM codes [2]. Several research projects such as the OC3 [3], OC4 [4] and OC5 [5] projects focus on the simulation of FHAWTs. To study the seakeeping of Floating Offshore Wind Turbines (FOWTs), it has been chosen to couple an unsteady free vortex wake aerodynamic solver (CACTUS) to a seakeeping code (InWave [6]). The free vortex wake theory assumes a potential flow but inherently models rotor/wake interactions and skewed rotor configurations. It shows a good compromise between accuracy and computational time. A first code-to-code validation has been done with results from FAST [7]on the FHAWT OC3 test case [3] considering the NREL 5MW wind turbine on the OC3Hywind SPAR platform. The code-to-code validation includes hydrodynamics, moorings and control (in torque and blade pitch). It shows good agreement between the two codes for small amplitude motions, discrepancies arise for rougher sea conditions due to differences in the used aerodynamic models.

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