Study of Active Rotor Control for In-Plane Rotor Noise Reduction

2019 ◽  
Vol 56 (1) ◽  
pp. 179-190 ◽  
Author(s):  
Tianxiao Yang ◽  
Kenneth S. Brentner ◽  
Ethan Corle ◽  
Sven Schmitz
Keyword(s):  
Noise Reduction ◽  
Rotor Noise ◽  
Active Rotor Control ◽  
Rotor Control

scholarly journals Noise power spectral density scaled SNR response estimation with restricted range search for sound source localisation using unmanned aerial vehicles

2020 ◽  
Vol 2020 (1) ◽  
Author(s):  
Benjamin Yen ◽  
Yusuke Hioka
Keyword(s):  
Spectral Density ◽  
Noise Reduction ◽  
Power Spectral Density ◽  
Sound Source ◽  
Processing Algorithm ◽  
Post Processing ◽  
Time Frequency ◽  
Distance Error ◽  
Rotor Noise ◽  
Power Spectral

Abstract A method to locate sound sources using an audio recording system mounted on an unmanned aerial vehicle (UAV) is proposed. The method introduces extension algorithms to apply on top of a baseline approach, which performs localisation by estimating the peak signal-to-noise ratio (SNR) response in the time-frequency and angular spectra with the time difference of arrival information. The proposed extensions include a noise reduction and a post-processing algorithm to address the challenges in a UAV setting. The noise reduction algorithm reduces influences of UAV rotor noise on localisation performance, by scaling the SNR response using power spectral density of the UAV rotor noise, estimated using a denoising autoencoder. For the source tracking problem, an angular spectral range restricted peak search and link post-processing algorithm is also proposed to filter out incorrect location estimates along the localisation path. Experimental results show the proposed extensions yielded improvements in locating the target sound source correctly, with a 0.0064–0.175 decrease in mean haversine distance error across various UAV operating scenarios. The proposed method also shows a reduction in unexpected location estimations, with a 0.0037–0.185 decrease in the 0.75 quartile haversine distance error.

Recent Research in Rotor-Noise Reduction

1969 ◽  
Author(s):  
Harry Sternfeld ◽  
Robert H. Spencer
Keyword(s):  
Noise Reduction ◽  
Rotor Noise

A Contra-Rotating Open Rotor Noise Reduction Methodology by Using Anhedral Blade Tip

2021 ◽  
pp. 1-26
Author(s):  
Tianxiao Yang ◽  
Wenjun Yu ◽  
Dong Liang ◽  
Xiang He ◽  
Zhenguo Zhao
Keyword(s):  
Noise Reduction ◽  
Polar Angle ◽  
Aerodynamic Performance ◽  
Tip Vortex ◽  
Rotor Noise ◽  
Lean Angle ◽  
Open Rotor ◽  
Blade Tip

Abstract In this paper, a novel Contra-Rotating Open Rotor (CROR) noise reduction methodology based upon the anhedral blade tip applied to the front blade is developed. Results indicate that anhedral blade tip can provide noise reduction over 60 deg. polar angle range in both upstream and downstream areas at takeoff condition. The noise reduction becomes more significant as the lean angle of anhedral blade tip increases, and the maximum noise reduction is over 4 dB. Further analysis shows that anhedral blade tip decreases the strength and size of blade tip vortex shed from the front blade, and reduces its interaction with the rear rotor, which decreases the fluctuation of loading acting on the rear rotor and its loading noise. Furthermore, the anhedral blade tip does not have strong effect on the aerodynamic performance of CROR at cruise.

scholarly journals Reduction of helicopter blade-vortex interaction noise by active rotor control technology

1997 ◽  
Vol 33 (9-10) ◽  
pp. 647-687 ◽  
Author(s):  
Yung H. Yu ◽  
Bernd Gmelin ◽  
Wolf Splettstoesser ◽  
Jean J. Philippe ◽  
Jean Prieur ◽  
...  
Keyword(s):  
Control Technology ◽  
Vortex Interaction ◽  
Helicopter Blade ◽  
Blade Vortex Interaction ◽  
Active Rotor Control ◽  
Rotor Control

scholarly journals Aerodynamic Evaluation of Miniature Trailing-Edge Effectors for Active Rotor Control

2011 ◽  
Vol 48 (3) ◽  
pp. 995-1004 ◽  
Author(s):  
Claude G. Matalanis ◽  
Brian E. Wake ◽  
Daniel Opoku ◽  
Byung-Young Min ◽  
Nandita Yeshala ◽  
...  
Keyword(s):  
Trailing Edge ◽  
Active Rotor Control ◽  
Rotor Control

Towards counter-rotating open rotor noise reduction via radiation efficiency considerations

2019 ◽  
Author(s):  
Csaba Horváth ◽  
Bence Fenyvesi ◽  
Bálint Kocsis ◽  
Michael Quaglia ◽  
Stéphane Moreau ◽  
...  
Keyword(s):  
Noise Reduction ◽  
Radiation Efficiency ◽  
Rotor Noise ◽  
Open Rotor

The Prediction and Analysis of Helicopter Rotor Rotation Noise in Hover

2013 ◽  
Vol 397-400 ◽  
pp. 291-294
Author(s):  
Da Wei Liu ◽  
Pei Lin Huang ◽  
Jin Zu Ji
Keyword(s):  
Noise Reduction ◽  
Helicopter Rotor ◽  
Rotor Speed ◽  
Characteristic Analysis ◽  
Directional Characteristic ◽  
Rotor Rotation ◽  
Prediction Program ◽  
Rotor Noise

A prediction program for analysis of helicopter rotor rotation noise was developed based on Farassat1A formulation. The acoustic prediction program was validated by the comparison with the WOPWOP program results in the literature.The loads input for the acoustic calculation are obtained from CFD calculation. The directional characteristic analysis was conducted by this program. Some calculations were conducted for evaluating the influence of rotor parameters including rotor speed , blade pitch ,and blade dihedral for the helicopter rotor rotation noise in hover. The results show that some proper changes of rotor parameters can bring benefit in thickness and loading noise of helicopter rotor. Several conductive conclusions were summarized for the helicopter rotor noise reduction.

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