Noise Reduction in a High Lift Wing Using SMAs: Computational Fluid-Structural Analysis

Abstract

The leading-edge-slat on an aircraft is a significant contributor to the airframe noise during the low speed maneuvers of approach and landing. It has been shown in previous work that the slat noise may be reduced with a slat-cove filler (SCF). The objective of this current work is to determine how the SMA SCF behaves under steady flow using finite element structural models and finite volume (FV) fluid models based on a scaled wind tunnel model of a newly considered multi-element wing with a SCF. Computational fluid dynamics (CFD) analysis of the wing is conducted at multiple angles of attack, different flow speeds and high lift device deployment states. The FV fluid models make use of overset meshes, which overlap a slave mesh (that can undergo movement and deformation) unto a fixed master mesh, allowing for retraction and deployment of the slat and flap in the CFD analysis. The structural and fluid models are linked using a previously developed framework that permits the use of custom user material subroutines (for superelastic response of the SMA material) in the structural model, allowing for the performance of fluid-structure interaction (FSI) analysis. The fluid and structural solvers are weakly coupled such that the fluid solver transfers pressure data and the structural solver transfers displacements, but the physical quantities of each program are solved independently. FSI results are shown for the cases of the slat/SCF in the fully-deployed configuration as well as for the case of the slat/SCF undergoing retraction in flow.

Design of Shape-Adaptive Deployable Slat-Cove Filler for Airframe Noise Reduction

“…All models are based on a full-scale, freestream-aligned, high-lift airfoil section extracted from the midspan of the Boeing/ NASA Common Research Model (CRM) [41,42]. The models are developed in a similar manner as wind tunnel-scale structure and fluid models from previous work [6,33,[36][37][38]. The geometry employed herein includes an additional SCF profile.…”

“…Following the benchtop models, structural finite element models of the SMA-based SCF design were developed, and optimization was performed with a focus of reducing actuation force required to stow the SCF [33]. Work then shifted toward the development of both computational fluid dynamics (CFD) and fluid/structure interaction (FSI) models to assess the SCF behavior in relevant flowfield environments [36][37][38]. Concurrently with the computational CFD/FSI model development, a scaled physical model with deployable slat/ flaps and a SMA SCF was built.…”

“…Here, we propose and test a design methodology that uses finite element structural analysis and CFD simulations. While previous work has focused predominantly on using SMA materials for the SCF [6,33,[36][37][38], a novelty of the present Paper is the consideration of lightweight composite materials for the first time. In particular, the influence of material selection is investigated by comparing three SCF configurational classes:…”

Computational Modeling of a Mechanized Bench-Top Apparatus for Leading-Edge Slat Noise Treatment Device Prototypes

“…Recent work has studied means to further reduce actuation requirements 15 . Study of the static and dynamic, fluid-structure-interaction (FSI) behavior of the highly-flexible SCF structural system has also recently been undertaken 16 .…”

“…Simplified computational models were previously developed to analyze the SCF [12][13][14][15][16] and SGF 24 performance under aerodynamic and retract/deploy loads. The objectives of the present work were to develop finite element (FE) models of the mechanized benchtop SCF and SGF apparatus for refined prediction of the structural performance, practical estimation of actuator authority requirements, and eventual comparison with experimental results.…”