Experimental Investigation of the Effects of Leading-Edge Serration on the Blades of Savonius Wind Turbine

Alasvand, Sahel; Kazemi, Mostafa; Mani, Mahmood

doi:10.22034/jast.2023.398694.1150

Experimental Investigation of the Effects of Leading-Edge Serration on the Blades of Savonius Wind Turbine

Document Type : Original Article

Authors

Sahel Alasvand

Mostafa Kazemi

Mahmood Mani

Aerospace Engineering Department, Amirkabir University of Technology

10.22034/jast.2023.398694.1150

Abstract

The noise of wind turbines is mainly of aerodynamic origin and is caused by the impact of the flow on the turbine blade. Therefore, improving the behaviour of the flow around the turbine and reducing aeronoise can result in reducing its annoying noise. In the first step of this research, a suitable serration is selected according to the physics of the flow, and then it is installed on the leading edge of the blade in such a way that it does not cause the power loss of the turbine. All the studies have been done experimentally in the wind tunnel and with the help of power, pressure and air velocity measurements in the wake and in the different free stream velocities. The results showed that the pressure fluctuations in the model equipped with a serrated blade have decreased by 4-9% on average in different areas compared to the simple Savonius. On the other hand, the results of the frequency analysis of the anemometer sensors also showed that in the dominant frequencies, the serration caused the range of phenomena to decrease. These results were obtained in such a way that the power measurement showed that the maximum power value of the turbine equipped with serrated blade experienced an increase of nearly 19%. On the other hand, the velocity profile in the wake also shows a greater deficit in the flow around the modified Savonius, which confirms the decrease in the output momentum from the turbine and consequently the increase in power.

Keywords

Savonius

Wind Turbine

Aeronoise

Experimental Aerodynamics

Wind Tunnel

Subjects

Aerodynamic

[1] E. Pedersen, K. Persson Waye, "Perception and annoyance due to wind turbine noise—a dose–response relationship, " The Journal of the Acoustical Society of America., 116(6): p. 3460-3470,2004.

[2] F. Avallone, et al.,"Noise reduction mechanisms of sawtooth and combed-sawtooth trailing-edge serrations, " Journal of Fluid Mechanics., 848: p. 560-591, 2018.

[3] C.H.T. and J.L. Liu. "Bionic Design Review of Wind Turbine Blades, " in Advanced Materials Research., Trans Tech Publ,2012.

[4] F. Wenehenubun, A. Saputra and H. Sutanto, " An experimental study on the performance of Savonius wind turbines related with the number of blades, " Energy procedia.,68: p. 297-304, 2015.

[5] C. León, et al., " Boundary layer characterization and acoustic measurements of flow-aligned trailing edge serrations, " Experiments in fluids., 57(12): p. 1-22, 2016.

[6] L. Chen, J. Chen and Z. Zhang, "Review of the Savonius rotor's blade profile and its performance, " Journal of Renewable and Sustainable Energy., 10(1): p. 013306 ,2018.

[7] A. Zakaria and M. Ibrahim. "Effect of twist angle on starting capability of a Savonius rotor–CFD analysis, " in IOP Conference Series: Materials Science and Engineering, IOP Publishing., 2020.

[8] S. Wagner, R. Bareiß and G. Guidati, "Noise Mechanisms of Wind Turbines, " in Wind Turbine Noise Springer., p. 67-92 ,1996.

[9] C. Pearson," Vertical axis wind turbine acoustics.", University of Cambridge.,2014.

[10] S. Oerlemans, " Wind turbine noise: primary noise sources. ", 2011.

[11] M. Howe, "Aerodynamic noise of a serrated trailing edge. " Journal of Fluids and Structures., 5(1): p. 33-45,1991.

[12] P. Chaitanya, et al., " Performance and mechanism of sinusoidal leading-edge serrations for the reduction of turbulence–aerofoil interaction noise. " Journal of Fluid Mechanics., 818: p. 435-464,2017.

[13] S. Lee. "Wind turbine noise reduction by means of serrated trailing edges. " In INTER-NOISE and NOISE-CON Congress and Conference Proceedings. Institute of Noise Control Engineering.,2012.

[14] K. Gharali,N. Tam and D.A. Johnson. "A PIV load and flow structure study of a serrated dynamic airfoil. " in Lisbon 17th Int. Symp. On Applications of Laser Techniques to Fluid Mechanics., Lisbon, Portugal. 2014.

[15] J. Mathew, et al. " Serration design methodology for wind turbine noise reduction. " In Journal of Physics: Conference Series. IOP Publishing,2016.

[16] Z. Wang and M. Zhuang, " Leading-edge serrations for performance improvement on a vertical-axis wind turbine at low tip-speed-ratios. " Applied Energy, 208: p. 1184-1197,2017