Noise produced by unsteady flow around aircraft structures, termed airframe noise, is an important source of aircraft noise during the approach and landing phases of flight. Conventional leading-edge-slat devices for high lift on typical transport aircraft are a prominent source of airframe noise. Many concepts for slat noise reduction have been investigated. Slat-cove fillers have emerged as an attractive solution, but they maintain the gap flow, leaving some noise production mechanisms unabated, and thus represent a nonoptimal solution. Drooped-leading-edge (DLE) concepts have been proposed as "optimal" because the gap flow is eliminated. The deployed leading edge device is not distinct and separate from the main wing in DLE concepts and the high-lift performance suffers at high angles of attack () as a consequence. Elusive high- performance and excessive weight penalty have stymied DLE development. The fact that high-lift performance of DLE systems is only affected at high  suggests another concept that simultaneously achieves the high-lift of the baseline airfoil and the noise reduction of DLE concepts. The concept involves utilizing a conventional leading-edge slat device and a deformable structure that is deployed from the leading edge of the main wing and closes the gap between the slat and main wing, termed a slat-gap filler (SGF). The deployable structure consists of a portion of the skin of the main wing and it is driven in conjunction with the slat during deployment and retraction. Benchtop models have been developed to assess the feasibility and to study important parameters. Computational models have assisted in the bench-top model design and provided valuable insight in the parameter space as well as the feasibility. NomenclatureA = planform area CL = lift coefficient Cp = pressure coefficient Cusp = lower trailing edge of slat DLE = drooped leading edge L = aerodynamic lift OML = outer mold line RoFC = region of fixed curvature SCF = slat-cove filler SGF = slat-gap filler SMA = shape memory alloy  = angle of attack  = mass density  Af ,  As = austenite finish/start critical stress 1 Research Engineer, Structural Acoustics Branch, 2 N Dryden Street/Mail Stop 463, AIAA Senior Member 2 Designer III, TEAMS2 -Structural Dynamics Branch, 4B W Taylor Street/Mail Stop 230 Downloaded by PURDUE UNIVERSITY on July 31, 2015 | http://arc.aiaa.org |

Airframe noise is a growing concern in the vicinity of airports because of population growth and gains in engine noise reduction that have rendered the airframe an equal contributor during the approach and landing phases of flight for many transport aircraft. The leading-edge-slat device of a typical high-lift system for transport aircraft is a prominent source of airframe noise. Two technologies have significant potential for slat noise reduction; the slat-cove filler (SCF) and the slat-gap filler (SGF). Previous work was done on a 2D section of a transport-aircraft wing to demonstrate the implementation feasibility of these concepts. Benchtop hardware was developed in that work for qualitative parametric study. The benchtop models were mechanized for quantitative measurements of performance. Computational models of the mechanized benchtop apparatus for the SCF were developed and the performance of the system for five different SCF assemblies is demonstrated.