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

Abstract For a long period of time, researchers have been using analytical models to predict wake characteristics behind wind turbines in wind farms. Early models were weak and just depicted an approximation of wake shape. Based on those models, wake profile looks like a hat. A large number of analytical and numerical simulations were performed to predict the velocity profile in wind farm; some of them can predict both wake shape and velocity magnitude while some cannot reach the real magnitude of the velocity. In this study, a hybrid method based on blade element momentum (BEM) and computational fluid dynamics (CFD) is employed in order to investigate the actual shape of the wake using actuator disc (AD) model which represents the wind turbine. Different turbulence models are examined to investigate the effect of turbulence models on wake shape. It is shown that the wake shape depends on the induction factor which is calculated using (BEM) theory and assuming a constant induction factor leads to some errors. Comparison between recent study and old analytical models shows that the numerical approach is more accurate almost in far wake because of considering the effect of turbulence. Again, in the recent survey, a simple model is presented in order to simulate the hub. It is concluded that the hub has a great effect on downstream wake and should be taken into account. In this new approach, the error of wake modeling using AD significantly decreased.

[1]  B. G. Newman.  Actuator-disc theory for vertical-axis wind turbines , 1983 .

[2]  Robert Howell,et al.  A hybrid actuator disc - full rotor CFD methodology for modelling the effects of wind turbine wake interactions on performance , 2015 .

[3]  H. Hangan,et al.  Flow characterization in the near‐wake region of a horizontal axis wind turbine , 2016 .

[4]  H. Panofsky,et al.  Atmospheric Turbulence: Models and Methods for Engineering Applications , 1984 .

[5]  Niels N. Sørensen,et al.  General purpose flow solver applied to flow over hills , 1995 .

[6]  Xin Cai,et al.  Unsteady aerodynamics simulation of a full-scale horizontal axis wind turbine using CFD methodology , 2016 .

[7]  M.R.H. Nobari,et al.  Improvement of wind turbine performance using a novel tip plate structure , 2016 .

[8]  Imran Amin,et al.  Optimization of wind turbine micrositing: A comparative study , 2012 .

[9]  R. Bontempo,et al.  The axial momentum theory as applied to wind turbines: some exact solutions of the flow through a rotor with radially variable load , 2017 .

[10]  Amir Nejat,et al.  Aerodynamic optimization of a 5 Megawatt wind turbine blade , 2016 .

[11]  S. Loyer,et al.  Spatial study of the wake meandering using modelled wind turbines in a wind tunnel , 2011 .

[12]  Abdolrahman Dadvand,et al.  Aerodynamic shape optimization and analysis of small wind turbine blades employing the Viterna approach for post-stall region , 2016 .

[13]  R. Mikkelsen.  Actuator Disc Methods Applied to Wind Turbines , 2004 .

[14]  Longyan Wang,et al.  Comparison of the effectiveness of analytical wake models for wind farm with constant and variable hub heights , 2016 .

[15]  N. Jensen.  A note on wind generator interaction , 1983 .

[16]  Sepehr Sanaye,et al.  Multi-objective optimization of airfoil shape for efficiency improvement and noise reduction in small wind turbines , 2014 .

[17]  J. Sørensen,et al.  Analysis of wake states by a full‐field actuator disc model , 1998 .

[18]  M. Y. Hussaini,et al.  Placement of wind turbines using genetic algorithms , 2005 .

[19]  Andrew Kusiak,et al.  Design of wind farm layout for maximum wind energy capture , 2010 .

[20]  Velraj Ramalingam,et al.  Wake prediction of horizontal-axis wind turbine using full-rotor modeling , 2014 .

[21]  J. Højstrup,et al.  A Simple Model for Cluster Efficiency , 1987 .

[22]  Ahmad Sedaghat,et al.  Aerodynamic design of a 300 kW horizontal axis wind turbine for province of Semnan , 2012 .

[23]  Carlo Poloni,et al.  Optimization of wind turbine positioning in large windfarms by means of a genetic algorithm , 1994 .

[24]  M.R.H. Nobari,et al.  Prediction of optimum section pitch angle distribution along wind turbine blades , 2013 .

[25]  Takao Maeda,et al.  Experimental and numerical investigation of the effect of turbulent inflow on a Horizontal Axis Wind Turbine (part II: Wake characteristics) , 2016 .

[26]  Mojtaba Tahani,et al.  Aerodynamic optimal design of wind turbine blades using genetic algorithm , 2014 .

[27]  Pourya Alamdari,et al.  Aerodynamic design and economical evaluation of site specific small vertical axis wind turbines , 2013 .

[28]  Rebecca J. Barthelmie,et al.  Analytical modelling of wind speed deficit in large offshore wind farms , 2006 .

[29]  Jonathan W. Naughton,et al.  Wind Turbine Blade Design for Subscale Testing , 2016 .

[30]  Mahdi Nili-Ahmadabadi,et al.  Performance improvement of a wind turbine blade using a developed inverse design method , 2016 .

[31]  B. Koren,et al.  Review of computational fluid dynamics for wind turbine wake aerodynamics , 2011 .

[32]  Chris T. Kiranoudis,et al.  Short-cut design of wind farms , 2001 .

[33]  Farschad Torabi,et al.  Considering induction factor using BEM method in wind farm layout optimization , 2014 .

[34]  Francesco Castellani,et al.  An application of the actuator disc model for wind turbine wakes calculations , 2013 .

[35]  Mohamed Saighi,et al.  CFD wind turbines wake assessment in complex topography , 2017 .

[36]  Luciano Castillo,et al.  Unrestricted wind farm layout optimization (UWFLO): Investigating key factors influencing the maximum power generation , 2012 .

[37]  S. Hoerner.  Fluid Dynamic Drag: Practical Information on Aerodynamic Drag and Hydrodynamic Resistance , 1965 .

[38]  Muyiwa S. Adaramola,et al.  Performance and near wake measurements of a model horizontal axis wind turbine , 2012 .

[39]  Francesco Castellani,et al.  Wake Modeling with the Actuator Disc Concept , 2012 .

[40]  Alireza Javaheri,et al.  A semi-analytical model for velocity profile at wind turbine wake using blade element momentum , 2015 .

[41]  Bryan A. Norman,et al.  Heuristic methods for wind energy conversion system positioning , 2004 .