scholarly journals Serrated slat cusp for high-lift device noise reduction

2021 ◽  
Vol 33 (1) ◽  
pp. 015107
Author(s):  
Hasan Kamliya Jawahar ◽  
Syamir Alihan Showkat Ali ◽  
Mahdi Azarpeyvand
Keyword(s):  
Noise Reduction ◽  
High Lift ◽  
Device Noise

Device Noise Reduction for Silicon Nanowire Field-Effect-Transistor Based Sensors by Using a Schottky Junction Gate

ACS Sensors ◽  
2019 ◽  
Vol 4 (2) ◽  
pp. 427-433 ◽  
Author(s):  
Xi Chen ◽  
Si Chen ◽  
Qitao Hu ◽  
Shi-Li Zhang ◽  
Paul Solomon ◽  
...  
Keyword(s):  
Noise Reduction ◽  
Field Effect ◽  
Field Effect Transistor ◽  
Silicon Nanowire ◽  
Schottky Junction ◽  
Effect Transistor ◽  
Device Noise

Experimentation and Computational Assessment of an SMA-Based Slat-Cove Filler For Noise Reduction in a High Lift Wing

2017 ◽  
Author(s):  
William D. Scholten ◽  
Ryan Patterson ◽  
Quentin Chapelon ◽  
Darren J. Hartl ◽  
Thomas W. Strganac ◽  
...  
Keyword(s):  
Noise Reduction ◽  
High Lift

Nascent Noise Reduction Strategies for Underwater Vehicles

Volume 1 ◽  
2004 ◽  
Author(s):  
Promode R. Bandyopadhyay
Keyword(s):  
Noise Reduction ◽  
Artificial Muscle ◽  
Underwater Vehicles ◽  
Drive Train ◽  
Forward Speed ◽  
High Lift ◽  
Radiated Noise ◽  
Rotational Rate ◽  
Reduction Strategies

Noise reduction concepts applicable to small underwater vehicles and in the nascent stages of research, are considered. These questions are asked. How to lower the propulsor rotational rate while maintaining forward speed? How to reduce blade tonal? How to supplant the propulsor drive train, which is the main source of hull vibration and radiated noise? The highlights of progress in passive and active approaches are reviewed. The approaches are inspired by unsteady high lift principles employed in flying and swimming animals and by emerging artificial muscle technology.

scholarly journals Numerical investigation of porous materials for trailing edge noise reduction

2020 ◽  
Vol 19 (6-8) ◽  
pp. 347-364
Author(s):  
Lennart Rossian ◽  
Roland Ewert ◽  
Jan W Delfs
Keyword(s):  
Noise Reduction ◽  
Porous Materials ◽  
Collaborative Research ◽  
Smooth Transition ◽  
Trailing Edge ◽  
High Lift ◽  
Trailing Edge Noise ◽  
Numerical Investigations ◽  
Civil Aircraft ◽  
Numerical Approaches

In the framework of the German Collaborative Research Center CRC 880: Fundamentals of High Lift for Future Civil Aircraft porous materials as a means towards the reduction of airfoil trailing edge noise are investigated. At DLR, both experimental and numerical approaches are pursued to understand the physics behind the noise reduction. The present paper focuses on the numerical investigations, for which the experimental data serves as an evaluation basis. From the analysis of homogeneous materials, first steps are made towards the design of aeroacoustically tailored materials. It is assumed that materials with locally varying permeability may be suitable to achieve maximum noise reduction, as they provide a smooth transition from the solid airfoil to the free flow in the wake. The simulation results support this understanding, however it is revealed that high local gradients in the material properties themselves may act as acoustic sources.

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.

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