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.