Approaches for Improved High-Lift Performance of Slotted Natural Laminar Flow Airfoils

Abstract

Unsteady active flow control methods are applied to a slotted natural laminar flow airfoil through the use of computational fluid dynamics. Three different actuation methods: pulsed blowing, traverse actuation, and thermal actuation are examined through a sensitivity study to guide the maturation of this technology for potential use in a next generation aircraft. Pulsed blowing demonstrated that higher mass flows and lower frequencies were more efficient, although steady blowing was still more efficient. Traverse actuation, modeled as a 2D approximation of a 3D technique, was shown to be more efficient than both steady and pulsed blowing. The results from computational simulations of the thermal actuation method are in good agreement with the expected trends from gas dynamics principles, illustrating that higher supply temperature provides the same performance improvements but with lower mass flow. This suggests that a practical implementation of an efficient flow control system might use a high temperature source for actuation, such as an anti-ice system.