Wake Measurements of Small-Scale Vertical Axis Wind Turbines at Politecnico Di Milano: A Critical Review

  • G. PersicoEmail author
  • V. Dossena
  • A. Zasso
Conference paper
Part of the Green Energy and Technology book series (GREEN)


In the last ten years, four measurement campaigns were performed at Politecnico di Milano on two Darrieus Vertical Axis Wind Turbines (VAWT) for micro-generation of different architecture (H-shaped vs troposkien), but sharing the blade number (3), the blade profile (NACA 0021), and the swept area (1.5 m2). The experiments, carried out in the large-scale wind tunnel of Politecnico di Milano, included detailed wake measurements. This paper presents a review of the research activities related to velocity and turbulence measurements in the wake, proposing an analysis of both the technical aspects and the scientific outcomes of the investigation. In particular, the wakes of these turbines were measured on several surfaces downstream of the rotors for different tip speed ratios and different Reynolds numbers, searching for corresponding conditions between the two rotors. The paper first presents the technical issues involved in measuring the flow velocity in the wake of VAWT rotors with intrusive techniques such as hot wire anemometers and pressure probes. The second part of the paper proposes a comprehensive analysis of the wakes shed by the tested models. The wakes appear asymmetric and roughly follow the shape of the rotor, their width and velocity deficit being strongly dependent on the tip speed ratio. Flow angle measurements show the onset of large-scale tip vortices, for both the H-shape and the troposkien rotors, even though resulting from different aerodynamic mechanisms in the two architectures. A discussion on the impact of the wake features on the implementation of VAWTs in the urban environment concludes the paper.


VAWT H-shaped and troposkien rotors Wind tunnel testing Turbine wakes Hot-wire anemometry 



The present work is a result of the contributions from the DeepWind project, supported by the European Commission (FP7 Energy 2010 - Future emerging technologies), and the MIUR (Italian Ministry of Education, University and Research). The authors would like to express their gratitude to the Company Tozzi-Nord Wind Turbines, and to the technicians and collaborators of the Politecnico di Milano and the Università di Trento for their support in performing the experiments.


  1. 1.
    Balduzzi, F., Bianchini, A., Carnevale, E.A., Ferrari, L., Magnani, S.: Feasibility analysis of a Darrieus vertical-axis wind turbine installation in the rooftop of a building. Appl. Energy 97, 921–929 (2012)CrossRefGoogle Scholar
  2. 2.
    Mertens, S., van Kuik, G., van Bussel, G.: Performance of an H-Darrieus in the skewed flow on a roof. J. Solar Energy Eng. 125, 433–440 (2003)Google Scholar
  3. 3.
    Mertens, S.: Wind Energy in the Built Environment—Concentrator Effects of Buildings. Multi-science (2006)Google Scholar
  4. 4.
    Lee, K.Y., Tsao, S.H., Tzeng, C.W., Lin, H.J.: Influence of the vertical wind and wind direction on the power output of a small vertical-axis wind turbine installed on the rooftop of a building. Appl. Energy 209, 383–391 (2018)CrossRefGoogle Scholar
  5. 5.
    Battisti, L., Benini, E., Brighenti, A., Raciti Castelli, M., dell’Anna, S., Dossena, V., Persico, G., Schmidt Paulsen, U., Pedersen, T.F.: Wind tunnel testing of the DeepWind demonstrator in design and tilted operating conditions. Energy 111, 484–497 (2016)CrossRefGoogle Scholar
  6. 6.
    Shamsoddin, S., Porté-Agel, F.: Large eddy simulation of vertical axis wind turbine wakes. Energies 7(2), 890–912 (2014)Google Scholar
  7. 7.
    Mendoza, M., Bachant, P., Wosnik, M., Goude, A.: Validation of an actuator line model coupled to a dynamic stall model for pitching motions characteristic to vertical axis turbines. J. Phys. Conf. Ser. 753(2) (2016)Google Scholar
  8. 8.
    Schito, P., Zasso, A.: Actuator forces in CFD: RANS and LES modeling in OpenFOAM. J. Phys: Conf. Ser. 524, 012160 (2014)Google Scholar
  9. 9.
    Maskell, E.C.: A theory of the blockage effects on bluff bodies and stalled wings in enclosed wind tunnel, ARC/R & M-3400 (1963)Google Scholar
  10. 10.
    Mercker, E., Wiedemann, J.: On the correction of the interference effects in open jet wind tunnels, SAE Paper No. 960671 (1996)Google Scholar
  11. 11.
    Battisti, L., Zanne, L., Dell’Anna, S., Dossena, V., Persico, G., Paradiso, B.: Aerodynamic measurements on a vertical axis wind turbine in a large scale wind tunnel. J. Energy Res. Technol. 133, 031201 (2011)CrossRefGoogle Scholar
  12. 12.
    Dossena, V., Persico, G., Paradiso, B., Battisti, L., Dell’Anna, S., Brighenti, A., Benini, E.: An experimental study of the aerodynamics and performance of a vertical axis wind turbine in a confined and unconfined environment. J. Energy Res. Technol. 137, 051207 (2015)CrossRefGoogle Scholar
  13. 13.
    Persico, G., Dossena, V., Paradiso, B., Battisti, L., Brighenti, A., Benini, E.: Time-resolved experimental characterization of wakes shed by h-shaped and troposkien vertical axis wind turbines. ASME J. Energy. Res. Technol. 139(3), 031203 (11 pages) (2017)Google Scholar
  14. 14.
    Tescione, G., Ragni, D., He, C., Ferreira, C.S., van Bussel, G.: Near wake flow analysis of a vertical axis wind turbine by stereoscopic particle image velocimetry. Renew. Energy 70, 47–61 (2014)CrossRefGoogle Scholar
  15. 15.
    Peng, H., Lam, H., Lee, C.: Investigation into the wake aerodynamics of a five-straight-bladed vertical axis wind turbine by wind tunnel tests. J. Wind Eng. Ind. Aerodyn. 155, 23–35 (2016)CrossRefGoogle Scholar

Copyright information

© Springer International Publishing AG 2018

Authors and Affiliations

  1. 1.LFM - Laboratorio Di Fluidodinamica Delle Macchine, Dipartimento Di EnergiaPolitecnico Di MilanoMilanItaly
  2. 2.Dipartimento Di MeccanicaPolitecnico Di MilanoMilanItaly

Personalised recommendations