Calculation and Measurement of Induced Drag at Low Speeds

An overview is presented of the calculation and the measurement of induced drag with emphasis on moderate-to-high aspect ratio wings with vortex shedding restricted to the trailing-edge. The discussion concentrates on farfield techniques and is limited to low Mach number, steady flows in the absence of active systems such as surface blowing and propulsion. The calculation techniques are applied to three-dimensional flow field solutions obtained with potential and Euler codes. The effect of wake rollup on the induced drag is discussed. Also, induced drag measurements using wake-survey techniques are reviewed.