Leading-edge protuberances on airfoils or wings have been considered as a viable passive control method for flow separation. In this paper, the aerodynamic performance of a modified airfoil with a single leading-edge protuberance was investigated and compared with the baseline NACA 634-021 airfoil. Spalart–Allmaras turbulence model was applied for the numerical simulation. Compared to the sharp decline of baseline lift coefficient, the stall angle of the modified foil decreased and the decline of the lift coefficient became mild. The poststall performance of the modified airfoil was improved, while the prestall performance was declined. Asymmetric flows along the spanwise direction were observed on the modified airfoil, and the local region around one shoulder of the protuberance suffered from leading-edge separation at prestall angles of attack, which may be responsible for the performance decline. At poststall angles of attack, the attached flows along the peak of the protuberance with a sideward velocity component would help improving the total performance of the airfoil. Experimental visualization methods, including surface tuft and smoke flow, were performed, and the asymmetric flow pattern past the protuberance was successfully captured. This specific phenomenon may be largely related to the formation of the biperiodic condition and other complicated flow patterns induced by multiple leading-edge protuberances. The formation mechanism and suppression method of the symmetry breaking phenomenon should be investigated more deeply in the future to guide the practical application of this passive control method.
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February 2018
Research-Article
Effect of a Single Leading-Edge Protuberance on NACA 634-021 Airfoil Performance
Chang Cai,
Chang Cai
State Key Laboratory of
Hydroscience and Engineering,
Department of Thermal Engineering,
Tsinghua University,
Beijing 100084, China
e-mail: cai-c12@mails.tsinghua.edu.cn
Hydroscience and Engineering,
Department of Thermal Engineering,
Tsinghua University,
Beijing 100084, China
e-mail: cai-c12@mails.tsinghua.edu.cn
Search for other works by this author on:
Zhigang Zuo,
Zhigang Zuo
State Key Laboratory of
Hydroscience and Engineering,
Department of Thermal Engineering,
Tsinghua University,
Beijing 100084, China
e-mail: zhigang200@mail.tsinghua.edu.cn
Hydroscience and Engineering,
Department of Thermal Engineering,
Tsinghua University,
Beijing 100084, China
e-mail: zhigang200@mail.tsinghua.edu.cn
Search for other works by this author on:
Shuhong Liu,
Shuhong Liu
Mem. ASME
State Key Laboratory of
Hydroscience and Engineering,
Department of Thermal Engineering,
Tsinghua University,
Beijing 100084, China
e-mail: liushuhong@mail.tsinghua.edu.cn
State Key Laboratory of
Hydroscience and Engineering,
Department of Thermal Engineering,
Tsinghua University,
Beijing 100084, China
e-mail: liushuhong@mail.tsinghua.edu.cn
Search for other works by this author on:
Takao Maeda
Takao Maeda
Division of Mechanical Engineering,
Mie University,
Tsu, Mie 514-8507, Japan
e-mail: maeda@mach.mie-u.ac.jp
Mie University,
Tsu, Mie 514-8507, Japan
e-mail: maeda@mach.mie-u.ac.jp
Search for other works by this author on:
Chang Cai
State Key Laboratory of
Hydroscience and Engineering,
Department of Thermal Engineering,
Tsinghua University,
Beijing 100084, China
e-mail: cai-c12@mails.tsinghua.edu.cn
Hydroscience and Engineering,
Department of Thermal Engineering,
Tsinghua University,
Beijing 100084, China
e-mail: cai-c12@mails.tsinghua.edu.cn
Zhigang Zuo
State Key Laboratory of
Hydroscience and Engineering,
Department of Thermal Engineering,
Tsinghua University,
Beijing 100084, China
e-mail: zhigang200@mail.tsinghua.edu.cn
Hydroscience and Engineering,
Department of Thermal Engineering,
Tsinghua University,
Beijing 100084, China
e-mail: zhigang200@mail.tsinghua.edu.cn
Shuhong Liu
Mem. ASME
State Key Laboratory of
Hydroscience and Engineering,
Department of Thermal Engineering,
Tsinghua University,
Beijing 100084, China
e-mail: liushuhong@mail.tsinghua.edu.cn
State Key Laboratory of
Hydroscience and Engineering,
Department of Thermal Engineering,
Tsinghua University,
Beijing 100084, China
e-mail: liushuhong@mail.tsinghua.edu.cn
Takao Maeda
Division of Mechanical Engineering,
Mie University,
Tsu, Mie 514-8507, Japan
e-mail: maeda@mach.mie-u.ac.jp
Mie University,
Tsu, Mie 514-8507, Japan
e-mail: maeda@mach.mie-u.ac.jp
1Corresponding author.
Contributed by the Fluids Engineering Division of ASME for publication in the JOURNAL OF FLUIDS ENGINEERING. Manuscript received August 4, 2016; final manuscript received April 3, 2017; published online October 31, 2017. Assoc. Editor: Olivier Coutier-Delgosha.
J. Fluids Eng. Feb 2018, 140(2): 021108 (7 pages)
Published Online: October 31, 2017
Article history
Received:
August 4, 2016
Revised:
April 3, 2017
Citation
Cai, C., Zuo, Z., Liu, S., and Maeda, T. (October 31, 2017). "Effect of a Single Leading-Edge Protuberance on NACA 634-021 Airfoil Performance." ASME. J. Fluids Eng. February 2018; 140(2): 021108. https://doi.org/10.1115/1.4037980
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