Leveraging Surface Aeroacoustic-Structural Interaction for Airfoil Tonal Noise Reduction — A Parametric Study

2019 ◽  
Author(s):  
Irsalan Arif ◽  
Garret C. Y. Lam ◽  
Randolph C. K. Leung ◽  
Di Wu
Keyword(s):  
Noise Reduction ◽  
Parametric Study ◽  
Tonal Noise ◽  
Structural Interaction

Experimental study of wavy trailing edge serrations on flat rotor blades

2021 ◽  
Vol 263 (5) ◽  
pp. 1855-1866
Author(s):  
Sai Manikanta Kaja ◽  
K. Sriinivasan ◽  
A. Jaswanth Kalyan Kumar
Keyword(s):  
Experimental Study ◽  
Noise Reduction ◽  
Pitch Angle ◽  
Acoustic Emissions ◽  
Broadband Noise ◽  
Rotor Blades ◽  
Tonal Noise ◽  
Trailing Edge ◽  
Low Speeds ◽  
Trailing Edge Serrations

A detailed experimental study is conducted to observe the effect of various parameters like wavelength, depth of serrations, and pitch angle on serrated blades' acoustic emissions at low speeds up to 2000 rpm. Experiments are conducted on flat blade rotors with sinusoidal serrations on the trailing edge of blades with different amplitudes and wavelengths. A total of 7 blades with different serration configurations, including a base configuration, are studied, five of them have serrations throughout the span of the blade, and one configuration has serration of varying amplitude on the farther half of the blade. It is observed that some blade configurations have resulted in tonal noise reduction noise as much as 8dB, whereas some of the serration configurations reduce very little to none, there is no significant effect of T.E serrations on the broadband noise emitted by the rotor. Directivity of noise generated from the rotor, the effect of serrations on the directivity of the noise is studied.

scholarly journals Innovative passive multifrequency propeller device for noise and vibration reduction in turboprop fuselage

2018 ◽  
Vol 233 ◽  
pp. 00030 ◽  
Author(s):  
Angelo De Fenza ◽  
Maurizio Arena ◽  
Leonardo Lecce
Keyword(s):  
Noise Reduction ◽  
Tonal Noise ◽  
Research Activity ◽  
Noise Sources ◽  
Noise And Vibration ◽  
Aircraft Fuselage ◽  
Research Sector ◽  
Aeronautical Industry ◽  
Flight Regimes ◽  
Passive Noise

One of the main comfort issue affecting the passenger comfort into a turboprop aircraft fuselage is the propeller tonal noise and the related vibrations. It is well known that propeller rotation during flight generates the main noise sources, depending upon its rotational angular velocity, number of blades, power at shaft generating aircraft thrust and blades geometry. Thanks to the progress behind the control systems of the blades rotations, an innovative highly selective DVA has been conceived. The purpose of the research activity has been improving the performances of the standard passive tonal noise control system used for the BPF tuned noise and vibration attenuation in turboprop aircraft. Due to specific commercial need, the use of bi-tuned frequency can lead at a passive noise reduction at two RPM regimes. Generally, the turboprop aircrafts use only two RPM regimes: 100% at take-off, climb and approach, 86% during cruise, climb and descent. An innovative passive bi-tonal device capable to be tuned at two different frequencies in order to optimize the fuselage noise reduction at two different flight regimes (100% and 86%), has been designed and numerically verified. The functional effectiveness of the bi-frequential tuned device has been analysed by finite elements simulations on a linear beam, representative of the turboprop fuselage frame. The outcomes achieved within this activity encourage the advancement of this research sector, as a support to the needs of the turboprop aeronautical industry. According to the long experience gained by the research group, the proposed multifunctional concept can be a valid technology solution ready to be manufactured as well as validated in flight.

Tonal Noise Reduction for a Maneuverable Marine Hydrokinetic Cycloturbine Vehicle Using Turbine Clocking

2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Margalit Z. Goldschmidt ◽  
Michael L. Jonson ◽  
Joseph Horn
Keyword(s):  
Noise Reduction ◽  
Experimental Work ◽  
Tonal Noise ◽  
Aquatic Life ◽  
Acoustic Control ◽  
Acoustic Signature ◽  
Load Cells ◽  
Marine Hydrokinetic ◽  
Sustainable Power ◽  
Harmful Effects

Abstract A Marine Hydrokinetic (MHK) cycloturbine vehicle can exploit tidal currents to generate sustainable power and also has the ability to station keep and maneuver. The vehicle consists of four counterrotating cycloturbines, which radiate sound underwater. Acoustic control is important to curtail the vehicle’s vibrations and acoustic signature, potentially preventing harmful effects on aquatic life, as well as to reduce the vehicle’s fatigue for longer deployment. A method of reducing the radiated acoustics of the vehicle is determined for tones at foil passing frequency and multiples, by means of clocking the blades between turbines. Experimental work includes testing of a subscale demonstrator in ARL’s Reverberant Tank facility. Fixing the subscale demonstrator to a reaction frame in the tank provides the ability to measure the generated loads using load cells. These measurements verify the effects of turbine clocking on the radiated acoustics.

Passive airfoil tonal noise reduction by localized flow-induced vibration of an elastic panel

2020 ◽  
Vol 107 ◽  
pp. 106319
Author(s):  
Irsalan Arif ◽  
Garret C.Y. Lam ◽  
Di Wu ◽  
Randolph C.K. Leung
Keyword(s):  
Noise Reduction ◽  
Tonal Noise ◽  
Flow Induced Vibration

A compact active control system for tonal noise reduction in axial fans

Noise Notes ◽  
2007 ◽  
Vol 6 (3) ◽  
pp. 37-46
Author(s):  
Anthony Gerard ◽  
Alain Berry ◽  
Patrice Masson
Keyword(s):  
Control System ◽  
Noise Reduction ◽  
Active Control ◽  
Tonal Noise ◽  
Axial Fans ◽  
Active Control System

Exploring Airfoil Tonal Noise Reduction with Elastic Panel Using Perturbation Evolution Method

AIAA Journal ◽  
2020 ◽  
Vol 58 (11) ◽  
pp. 4958-4968 ◽  
Author(s):  
I. Arif ◽  
Di Wu ◽  
Garret C. Y. Lam ◽  
Randolph C. K. Leung
Keyword(s):  
Noise Reduction ◽  
Tonal Noise
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