Airfoil Drag Measurement with Simulated Leading-Edge Ice Using the Wake Survey Method

Biao Lu and Michael B. Bragg
University of Illinois, Urbana, Illinois, 61801


ABSTRACT
This paper investigated in detail the wakes of an S809 airfoil with and without a simulated leading-edge ice accretion, and an NACA 0012 airfoil with and without glaze ice shapes. The effects of turbulence on the profile drag determination using the wake-survey method were analyzed. A chamfered and a tapered Pitot probe were used to measure the total and static pressure, while an x-hotwire was used to determine the three components of turbulence in wakes. The effects of turbulence on total pressure measurements were considered. A new profile drag equation, derived by modifying van Dam's equation, was used to calculate the profile drag. Jones' equation was transformed to the same form as the new drag equation to estimate the implicit turbulence effects on drag determination. The results indicate that, the turbulence effects on drag determination should be considered. This is especially true as the turbulence intensity increases at high angles of attack. A relatively simple and accurate wake survey technique for accurate drag determination is demonstrated.





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