Induced Drag of a Simple Wing From Wake Measurements

Detailed flow surveys in the wake of a rectangular wing of aspect ratio six are described, which provide measurement of induced drag, profile drag, and lift. The investigation was conducted at 0.18 Mach number and 1.27 million chord Reynolds number employing a single five-hole probe for the measurement of total pressure and all three components of wake velocity. A comparison of wake data with balance data and wing theory demonstrates the excellent accuracy of low-speed wake measurements. Furthermore, the wake survey technique is shown to have good data repeatability and to accurately predict drag increments due to model modifications such as vortex generators. Spanwise distributions of induced drag, profile drag, and lift obtained from wake measurements are also presented.