Numerical Investigations on the Fluid Behavior in the Near Wake of an Experimental Wind Turbine Model in the Presence of the Nacelle

Document Type : Regular Article


1 Laboratory of Green and Mechanical Development (LGMD), École Nationale Polytechnique, B.P. 182, El-Harrach, Algiers, 16200, Algeria

2 Renewable Energy Development Center (CDER), B.P. 62, Route de l’Observatoire, Bouzaréah, Algiers, Algeria

3 Department of Mechanical Engineering, École de Technologie Supérieure, 1100 Notre-Dame Ouest, H3C1K3, Montréal, Québec, Canada



Accurate predictions of the near wake of horizontal-axis wind turbines are critical in estimating and optimizing the energy production of wind farms. Consequently, accurate aerodynamic models of an isolated wind turbine are required. In this paper, the steady-state flow around an experimental horizontal-axis wind turbine (known as the MEXICO model) is investigated using full-geometry computational fluid dynamics (CFD) simulations. The simulations are performed using Reynolds-Averaged Navier-Stokes (RANS) equations in combination with the transitional k-kl-w turbulence model. The multiple reference frame (MRF) approach is used to allow the rotation of the blades. The impacts of the nacelle and blade rotation on the induction region and near wake are highlighted. Simulation cases under attached and detached flow conditions with and without the nacelle were compared to the detailed particle image velocimetry (PIV) measurements. The axial and radial flow behaviors at the induction region have been analyzed in detail. This study attempts to highlight the nacelle effects on the near wake flow and on numerical prediction accuracy under various conditions, as well as the possible reasons for these effects. According to simulation results, the rotation of blades dominates the near wake region, and including the nacelle geometry can improve both axial and radial flow prediction accuracy by up to 15% at high wind speeds. At low wind speeds, the nacelle effects can be ignored. The presence of the nacelle has also been shown to increase flow separation at the trailing edges of the blade airfoils, increasing both root and tip vorticities. Finally, small nacelle diameters are recommended to reduce flow separation on the blades and increase the average velocity downstream of the rotor, thereby optimizing wind farm output power.


Abraham, A., T. Dasari and J. Hong (2019). Effect of turbine nacelle and tower on the near wake of a utility-scale wind turbine. Journal of Wind Engineering and Industrial Aerodynamics 193, 103981.##
Akay, B., D. Micallef, C. J. S. Ferreira and G. J. van Bussel (2014). Effects of geometry and tip speed ratio on the HAWT blade's root flow. Journal of Physics: Conference Series 555. IOP Publishing, 012002.##
ANSYS Fluent, A. (2017). ANSYS Fluent Documentation (version 18.1) ANSYS Inc.##
Bartl, J. and L. Sætran (2016). Experimental testing of axial induction based control strategies for wake control and wind farm optimization. Journal of Physics: Conference Series 753. IOP Publishing, p. 032035.##
Bastankhah, M. and F. Porté-Agel (2014). A new analytical model for wind-turbine wakes. Renewable Energy 70, 116-123.##
Boorsma, K. and J. Schepers (2014). New MEXICO experiment. Preliminary Overview with Initial Validation Technical Report ECN-E–14-048 ECN.##
Bouhelal, A., A. Smaili, O. Guerri and C. Masson (2018). Numerical investigation of turbulent flow around a recent horizontal axis wind Turbine using low and high Reynolds models. Journal of Applied Fluid Mechanics 11(1), 151-164.##
Dahlberg, J., S. Frandsen, H. A. Madsen, I. Antoniou, T. Friis Pedersen, R. Hunter and H. Klug (1999). Is the nacelle mounted anemometer an acceptable option in performance testing?. RISO-R-1114(EN)CONF-99031, 51-55.##
De Cillis, G., S. Cherubini, O. Semeraro, S. Leonardi and P. De Palma (2021). POD‐based analysis of a wind turbine wake under the influence of tower and nacelle. Wind Energy 24(6), 609-633.##
Feng, J., W. Z. Shen and Y. Li (2018). An optimization framework for wind farm design in complex terrain. Applied Sciences 8(11), 2053.##
Gao, Z., X. Feng, Z. Zhang, Z. Liu, X. Gao, L. Zhang, S. Li and Y. Li (2022). A brief discussion on offshore wind turbine hydrodynamics problem. Journal of Hydrodynamics 34(1), 15-30.  ##
Gao, Z., Y. Li, T. Wang, W. Shen, X. Zangh, S. Pröbsting, D. Li and R. Li (2021). Modelling the nacelle wake of a horizontal-axis wind turbine under different yaw conditions. Renewable Energy 172, 263-275.##
Guo, T., X. Guo, Z. Gao, S. Li, X. Zheng, X. Gao, R. Li, T. Wang, Y. Li and D. Li (2021). Nacelle and tower effect on a stand-alone wind turbine energy output—A discussion on field measurements of a small wind turbine. Applied Energy 303, 117590.##
Hansen, M. O. L., J. N. Sørensen, S. Voutsinas, N. Sørensen and H. A. Madsen (2006). State of the art in wind turbine aerodynamics and aeroelasticity. Progress in Aerospace Sciences 42(4), 285-330.##
Luo, J., R. Issa and A. Gosman (1994). Prediction of impeller-induced flow in mixing vessels using multiple frames of reference. 8th European conference on mixing. Institute of Chemical Engineers Symposium Series. p. 549-556.##
Madsen, H. A. and F. Rasmussen (2004). A near wake model for trailing vorticity compared with the blade element momentum theory. Wind Energy: An International Journal for Progress and Applications in Wind Power Conversion Technology 7(4), 325-341.##
Masson, C. and A. Smaili (2006). Numerical study of turbulent flow around a wind turbine nacelle. Wind Energy: An International Journal for Progress and Applications in Wind Power Conversion Technology 9(3), 281-298.##
Masson, C., A. Smaïli and C. Leclerc (2001). Aerodynamic analysis of HAWTs operating in unsteady conditions. Wind Energy: An International Journal for Progress and Applications in Wind Power Conversion Technology 4(1), 1-22.##
Micallef, D. (2012). 3D flows near a HAWT rotor: A dissection of blade and wake contributions. Doctoral thesis. Delft University of Technology.##
Micallef, D., G. van Bussel, C. S. Ferreira and T. Sant (2013). An investigation of radial velocities for a horizontal axis wind turbine in axial and yawed flows. Wind Energy 16(4), 529-544.##
Patankar, S. V. (2018). Numerical heat transfer and fluid flow: CRC press.##
Regodeseves, P. G. and C. S. Morros (2021). Numerical study on the aerodynamics of an experimental wind turbine: Influence of nacelle and tower on the blades and near-wake. Energy Conversion and Management 237, 114110.##
Sanderse, B., S. Van der Pijl and B. Koren (2011). Review of computational fluid dynamics for wind turbine wake aerodynamics. Wind Energy 14(7), 799-819.##
Santoni, C., K. Carrasquillo, I. Arenas‐Navarro and S. Leonardi (2017). Effect of tower and nacelle on the flow past a wind turbine. Wind Energy 20(12), 1927-1939.##
Schepers, J., K. Boorsma, S. Gomez-Iradi, P. Schaffarczyk, H. A. Madsen, N. N. Sørensen, W. Shen, T. Lutuz, C. Schulz, I. Herraez and S. Schreck (2014). Final report of IEA Wind Task 29: Mexnext (Phase 2).##
Schlichting, H., K. Gersten, E. Krause, H. Oertel and K. Mayes (1960). Boundary-layer theory (Vol. 7): Springer.##
Smaili, A. and C. Masson (2004). On the rotor effects upon nacelle anemometry for wind turbines. Wind Engineering 28(6), 695-713.##
Snel, H., J. Schepers and B. Montgomerie (2007). The MEXICO project (Model Experiments in Controlled Conditions): The database and first results of data processing and interpretation. Journal of Physics: Conference Series 75. IOP Publishing, p. 01201.##
Sørensen, J., W. Shen and X. Munduate (1998). Analysis of wake states by a full‐field actuator disc model. Wind Energy: An International Journal for Progress and Applications in Wind Power Conversion Technology 1(2), 73-88.##
Sørensen, N. N., A. Bechmann, P. E. Réthoré and F. Zahle (2014). Near wake Reynolds‐averaged Navier–Stokes predictions of the wake behind the MEXICO rotor in axial and yawed flow conditions. Wind Energy 17(1), 75-86.##
Sørensen, N. N., J. Michelsen and S. Schreck (2002). Navier–Stokes predictions of the NREL phase VI rotor in the NASA Ames 80 ft× 120 ft wind tunnel. Wind Energy: An International Journal for Progress and Applications in Wind Power Conversion Technology 5(2‐3), 151-169.##
Sørensen, N. N., F. Zahle, K. Boorsma and G. Schepers (2016). CFD computations of the second round of MEXICO rotor measurements. Journal of Physics: Conference Series 753. IOP Publishing, p. 022054.##
Tescione, G., C. S. Ferreira and G. Van Bussel (2016). Analysis of a free vortex wake model for the study of the rotor and near wake flow of a vertical axis wind turbine. Renewable Energy 87, 552-563.##
Thé, J. and H. Yu (2017). A Critical Review on the Simulations of Wind Turbine Aerodynamics Focusing on Hybrid RANS-LES Methods. Energy 138(1), 257-289.##
Thomsen, K., H. A. Madsen, G. C. Larsen and T. J. Larsen (2007). Comparison of methods for load simulation for wind turbines operating in wake. Journal of Physics: Conference Series 75. IOP Publishing, p. 012072.##
Walters, D. K. and D. Cokljat (2008). A three-equation eddy-viscosity model for Reynolds-averaged Navier–Stokes simulations of transitional flow. Journal of Fluids Engineering 130(12).##
Weihing, P., T. Wegmann, T. Lutz, E. Krämer, T. Kühn and A. Altmikus (2018). Numerical analyses and optimizations on the flow in the nacelle region of a wind turbine. Wind Energy Science 3(2), 503-531.##
Zahle, F. and N. N. Sørensen (2008). Overset grid flow simulation on a modern wind turbine. AIAA paper 6727, 2008.##
Zheng, Z., Z. Gao, D. Li, R. Li, Y. Li, Q. Hu and W. Hu (2018). Interaction between the atmospheric boundary layer and a stand-alone wind turbine in Gansu—Part II: Numerical analysis. SCIENCE CHINA Physics, Mechanics & Astronomy 61(9), 1-10.##
Zhu, X., C. Sun, H. Ouyang and Z. Du (2022). Numerical investigation of the effect of towers and nacelles on the near wake of a horizontal-axis wind turbine model. Energy 238, 121782.##