Airframe noise studies on wings with deployed high-lift devices

1998 ◽  
Author(s):  
Werner Dobrzynski ◽  
Kiyoshi Nagakura ◽  
Burkhard Gehlhar ◽  
Andreas Buschbaum
Keyword(s):  
High Lift ◽  
Airframe Noise

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

2016 ◽  
Author(s):  
William Scholten ◽  
Ryan Patterson ◽  
Darren Hartl ◽  
Thomas Strganac ◽  
Jeff Volpi ◽  
...  
Keyword(s):  
Structural Model ◽  
Leading Edge ◽  
Fluid Models ◽  
Cfd Analysis ◽  
High Lift ◽  
Airframe Noise ◽  
Weakly Coupled ◽  
Tunnel Model ◽  
Slat Noise ◽  
Flow Speeds

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.

Investigation of Airframe Noise from High Lift Configuration Model

2008 ◽  
Author(s):  
Hiroki Ura ◽  
Yuzuru Yokokawa ◽  
Taro Imamura ◽  
Takeshi Ito ◽  
Kazuomi Yamamoto
Keyword(s):  
Configuration Model ◽  
High Lift ◽  
Airframe Noise

DESIGN AND ANALYSIS OF RIGID-BODY SHAPE-CHANGE MECHANISM FOR AIRCRAFT WINGS

2015 ◽  
Vol 77 (21) ◽  
Author(s):  
Mohammad Hazrin Ismail ◽  
Shamsul Anuar Shamsudin ◽  
Mohd Nizam Sudin
Keyword(s):  
Shape Change ◽  
Rigid Bodies ◽  
Main Body ◽  
Programming Technique ◽  
High Lift ◽  
Airframe Noise ◽  
Aircraft Wings ◽  
Prismatic Joints ◽  
A Chain ◽  
Fixed End

Airframe noise reduction becomes a main interest among researchers who study the performance of aircrafts. The airframe noise can occur between the high-lift systems and main body of the airfoil. The proposed shape-changing airfoil is one of many ideas to reduce airframe noise by eliminating the gap between the main body and high-lift systems. This paper presents a new design of 30P30N airfoil, which converts the three-element airfoil (slat, main body and flap) into two-element airfoil (combination of slat and main body as an element and flap) by installing a shape-changing slat into the systems. This work applies a chain of rigid bodies connected by revolute and prismatic joints that are capable of approximating a shape change defined by a set of morphed slat design profiles. To achieve a single degree of freedom (DOF), a building-block approach is employed to mechanize the fixed-end shape-changing chain with the helped of Geometric Constraint Programming technique as an effective method to develop the mechanism. The conventional and shape-change 30P30N airfoils are compared to study the performances of airfoils with the velocity and angle of attack are constant.

scholarly journals Morphing Wing Droop Nose with Large Deformation: Ground Tests and Lessons Learned

Aerospace ◽  
2019 ◽  
Vol 6 (10) ◽  
pp. 111 ◽  
Author(s):  
Srinivas Vasista ◽  
Johannes Riemenschneider ◽  
Ralf Keimer ◽  
Hans Peter Monner ◽  
Felix Nolte ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Leading Edge ◽  
Lessons Learned ◽  
Morphing Wing ◽  
Hybrid Layer ◽  
High Lift ◽  
Airframe Noise ◽  
Design Synthesis ◽  
Bending Resistance ◽  
Curvature Distribution

A design for a new high lift system that features a morphing wing leading edge “droop nose” has the potential to generate high lift coefficients whilst mitigating airframe noise emissions. This seamless, continuous, and stepless flexible droop nose potentially offers improvements to stall and compressor requirements for an internally-blown active Coandă trailing edge flap. A full-scale, span-trimmed three-dimensional droop nose was manufactured and ground-tested based on results obtained from new design synthesis tools. A new component of the droop nose is the hybrid fiberglass-elastomeric skin that is tailored in stiffness to meet morphing curvature requirements and spanwise bending resistance. A manufacturing concept of the novel skin was established that led to an adequate manufacturing quality. The skin was driven and supported by two optimized kinematic ribs and conventional actuators and overall shape results show good agreement apart from the region closest to the leading edge. Kinematic trajectory measurements showed that the kinematics met the target trajectories well, with and without the influence of the skin, and it was deemed that the error in curvature is due to a higher than expected skin stiffness in the hybrid layer. Calculated actuator torque levels and strain measurements corroborate this inference. The lessons learned show that means of adjustment post-assembly are needed, and a reduction of torque, energy and a better curvature distribution may be achieved if the skin at the spar junction is allowed to move relative to the main wing. Careful aerodynamic, structural, actuation and manufacturing trade-off studies would be needed to determine the overall performance benefit.

In-Flight Deployable Micro Devices in Noise Control: Design and Evaluation

2011 ◽  
Author(s):  
Nesrin Sarigul-Klijn ◽  
Brian C. Kuo
Keyword(s):  
Noise Reduction ◽  
Sound Pressure Level ◽  
Sound Pressure ◽  
Aerodynamic Force ◽  
Three Dimensional ◽  
Pressure Level ◽  
Frequency Range ◽  
High Lift ◽  
Airframe Noise ◽  
Study Results

In this paper, time-accurate RANS simulations and FWH acoustic analogy were carried to study the three-dimensional unsteady flowfield and acoustic components around a three-element high-lift wing with and without micro devices. Micro devices are designed to be attached to the pressure side of the high lift surface near its trailing-edge to help reduce the noise generated. The analysis revealed that with the deployment of the micro device, along with reduced high-lift device setting angles, an overall airframe noise reduction of 2–5 dB is obtained over the entire frequency range. Noise reduction in the mid-frequency range, where human hearing is the most sensitive to, was particularly evident. As seen in an earlier 2D study by the authors, the application of the micro device caused strong aerodynamic force oscillations, resulting in a tone spike at a very low frequency. However, looking at the A-weighted scale sound pressure level spectrum, noise sources from the high-lift devices still dominated and it was the slat noise which dominated the overall 1/3 octave band sound pressure level. Through the reduced high-lift setting angles and the micro device application, an overall 2.3 dB noise reduction was achieved. Based on the current three-dimensional and the previous two-dimensional acoustic study results, micro devices designed by the authors demonstrated its potential to be applied onto commercial airliners as well as any aerial platforms for the use in airframe noise reduction during approach to landing phase of flight.

scholarly journals Aerodynamic Shape Optimisation of a Camber Morphing Airfoil and Noise Estimation

Aerospace ◽  
2022 ◽  
Vol 9 (1) ◽  
pp. 43
Author(s):  
Robert Valldosera Martinez ◽  
Frederico Afonso ◽  
Fernando Lau
Keyword(s):  
Lift Coefficient ◽  
Shape Optimisation ◽  
Structural Constraints ◽  
High Lift ◽  
Airframe Noise ◽  
Pressure Distributions ◽  
Discrete Adjoint ◽  
Coefficient Increase ◽  
Gradient Based ◽  
Optimisation Procedure

In order to decrease the emitted airframe noise by a two-dimensional high-lift configuration during take-off and landing performance, a morphing airfoil has been designed through a shape design optimisation procedure starting from a baseline airfoil (NLR 7301), with the aim of emulating a high-lift configuration in terms of aerodynamic performance. A methodology has been implemented to accomplish such aerodynamic improvements by means of the compressible steady RANS equations at a certain angle of attack, with the objective of maximising its lift coefficient up to equivalent values regarding the high-lift configuration, whilst respecting the imposed structural constraints to guarantee a realistic optimised design. For such purposes, a gradient-based optimisation through the discrete adjoint method has been undertaken. Once the optimised airfoil is achieved, unsteady simulations have been carried out to obtain surface pressure distributions along a certain time-span to later serve as the input data for the aeroacoustic prediction framework, based on the Farassat 1A formulation, where the subsequent results for both configurations are post-processed to allow for a comparative analysis. Conclusively, the morphing airfoil has proven to be advantageous in terms of aeroacoustics, in which the noise has been reduced with respect to the conventional high-lift configuration for a comparable lift coefficient, despite being hampered by a significant drag coefficient increase due to stall on the morphing airfoil’s trailing edge.

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