Active Skin for Turbulent Drag Reduction

Drag reduction for aerial vehicles has a range of positive ramifications: reduced fuel consumption with the associated economic and environmental consequences, larger flight range and endurance and higher achievable flight speeds. Recent numerical results yielded solid evidence that very small disturbances in the form of a spanwise traveling force wave on a surface could reduce drag by 70%. Our past efforts showed that the same effects can be accomplished by a surface deformation traveling wave. In this work, we propose to capitalize on our previous experience to develop a revolutionary ?smart? active skin for turbulent drag reduction. Traveling waves will be induced in the smart skin via active-material actuation. This is a ?micro-adaptive? flow control technique. Micro-scale wave amplitudes and energy inputs are sufficient to produce significant benefits. This device will be adaptive in the sense that wavelength, frequency and amplitude will be controlled on-line, in real-time, to produce optimal gains as the flow conditions change. Beyond the expected technological and scientific advances made during the project duration, the most important project deliverable will be a smart skin tailored for air vehicles.