Modares Mechanical Engineering

Modares Mechanical Engineering

A numerical study of slip velocity effects on a 2D airfoil dynamic analysis

Authors
Ehsan Bakhtiari 1
kobra gharali
Seyed Farshid Chini 2
1 School of mechanical engineering, College of engineering, University of Tehran, Tehran, IR Iran
2 Assistant Professor, Mechanical Engineering Department, University of Tehran
Abstract
Dynamic motion of a 2D SD7037 airfoil is investigated numerically in presence of a slip boundary condition. The dynamic motion of the airfoil is a harmonic oscillation, where the frequency and the amplitude of oscillations were adequate to airfoil to undergoing dynamic stall phenomenon. Dynamic stall occurred when the dynamic motion of the airfoil causes dynamic stall vortices, resulting in leading edge and trailing edge vortices which lead to rising the aerodynamic loads significantly. Analyzing the phenomena is challenging especially when a slip boundary condition exists near the airfoil wall. This particular condition is the general property of super-hydrophobic surfaces. These surfaces could potentially prevent the blade from icing. The main characteristic of these coatings is the appearance of a slip velocity on the wall. The slip velocity can affect the airfoil aerodynamics which is the main purpose of this paper. In this regard, a 2D airfoil with the Reynolds number of Re≈4×〖10〗^4 is analyzed using computational fluids dynamics (CFD). The Transition-SST model is applied. The results showed that not only the slip condition affects the aerodynamic loadings, but also the dynamic stall regimes changed considerably. So that for slip lengths higher than 100 micrometers, the maximum magnitude of the lift coefficient damped by 16%.
Keywords
wind turbine blade
Dynamic stall
Slip Boundary Condition
super-hydrophobicity
CFD

Subjects

[1] J. Herbert, S. Iniyan, E. Sreevalsan, S. Rajapandian, A review of wind energy technologies., Renew Sust Energy Rev., Vol. 11, pp. 1117-45, 2007.
[2] N. Dalili, A. Edrisy, R. Carriveau, A review of surface engineering issues critical to wind turbine performance, Renewable and Sustainable Energy Reviews, Vol. 13, pp. 428-438, 2009.
[3] P. Antikainen, S. Peuranen, Ice loads case study., in BOREAS V conference, 2000.
[4] W. Jasinski, S. Noe, M. Selig, M. Bragg, Wind turbine performance under icing conditions., Trans ASME J Sol Energy Eng, Vol. 120, pp. 60-5, 1998.
[5] L. Talhaug, K. Vindteknik, G. Ronsten, R. Horbaty, I. Baring-Gould, A. Lacroix, et. al, Wind energy projects in cold climates. 1st ed., Executive Committee of the International Energy Agency Program for Research and Development on Wind Energy Conversion Systems;, pp. 1-36, 2005.
[6] C. Antonini, M. Innocenti, T. Horn, M. Marengo, A. Amirfazli, Understanding the effect of superhydrophobic coatings on energy reduction in anti-icing systems, Cold Regions Science and Technology, Vol. 67, pp. 58-67, 2011.
[7] E. Bakhtiari, K. Gharali, S. F. Chini, Effects of superhydrophobic surfaces for a wind turbine blade element, in Proceeding of.
[8] C. Navier, Memoire sur les lois du mouvement des fluides., Mem. Acad. R. Sci. Inst. France., Vol. 6, pp. 389-440, 1823.
[9] R. B. Langtry, F. R. Menter, Correlation-Based Transition Modeling for Unstructured Parallelized Computational Fluid Dynamics Codes, AIAA, Vol. 47, No. 12, pp. 2894-2906, 2009.
[10] K. Gharali, D. A. Johnson, PIV-based load investigation in dynamic stall for different reduced frequencies, Exp Fluids, Vol. 55, pp. 1803, 2014.
Modares Mechanical Engineering
Volume 18, Issue 8
December 2018
Pages 183-192