Identification of low-frequency noise sources in high-speed train via resolution improvement

2015 ◽  
Vol 29 (9) ◽  
pp. 3609-3615 ◽  
Author(s):  
Hee-Min Noh ◽  
Jung-Woo Choi
Keyword(s):  
High Speed ◽  
Low Frequency ◽  
Frequency Noise ◽  
High Speed Train ◽  
Low Frequency Noise ◽  
Noise Sources ◽  
Resolution Improvement

Active Attenuation of Low Frequency Noise Radiated from Tunnel Exit of High Speed Train

1994 ◽  
Vol 13 (2) ◽  
pp. 39-47
Author(s):  
Min Liang ◽  
Toshiya Kitamura ◽  
Katsushi Matsubayashi ◽  
Toshifumi Kosaka ◽  
Tatsuo Maeda ◽  
...  
Keyword(s):  
Pressure Gradient ◽  
Pressure Wave ◽  
High Speed ◽  
Outer Space ◽  
Low Frequency ◽  
Close Relation ◽  
Frequency Noise ◽  
High Speed Train ◽  
Low Frequency Noise ◽  
Active Cancellation

A pressure wave occurs at the instant when a high speed train enters into a long tunnel. The wave propagates downstream to the tunnel exit and low frequency noise is radiated from the exit to outer space. The low frequency noise causes a lot of problems1 to the residents living near the exit and has a close relation with the pressure gradient of the pressure wave. To attenuate the low frequency noise, an active cancellation system rather than a passive one is developed. This research uses a model tunnel to examine the characteristic of the pressure wave and investigates the possibility to reduce the low frequency noise by reducing the pressure wave gradient with active cancellation.

Study of Low Frequency Noise Occurred from Tunnel Entrance of High Speed Train

2001 ◽  
Vol 2001.11 (0) ◽  
pp. 120-122
Author(s):  
Toshiya KITAMURA ◽  
Yasuhiko OKAWA ◽  
Toshikazu KATO ◽  
Shinji YAMADA
Keyword(s):  
High Speed ◽  
Low Frequency ◽  
Frequency Noise ◽  
High Speed Train ◽  
Low Frequency Noise ◽  
Tunnel Entrance

scholarly journals Low-Frequency Noise Radiated from a High-Speed Train Passing an Open Section

2007 ◽  
Vol 73 (735) ◽  
pp. 2275-2282 ◽  
Author(s):  
Hajime TAKAMI ◽  
Katsuhiro KIKUCHI ◽  
Hiroshi MAEKAWA ◽  
Takeshi KURITA ◽  
Yusuke WAKABAYASHI
Keyword(s):  
High Speed ◽  
Low Frequency ◽  
Frequency Noise ◽  
High Speed Train ◽  
Low Frequency Noise ◽  
Open Section

Active Control of Impulsive Low Frequency Noise Emitted from Tunnel Exit of High Speed Train

1998 ◽  
Vol 17 (3) ◽  
pp. 141-151
Author(s):  
Toshiya Kitamura ◽  
Min Liang ◽  
Makoto Uzawa ◽  
Masayuki Teranishi ◽  
Jun-Ichi Takano ◽  
...  
Keyword(s):  
Active Control ◽  
High Speed ◽  
Low Frequency ◽  
Frequency Noise ◽  
High Speed Train ◽  
Low Frequency Noise

125 Low-Frequency Noise Radiated from a High-speed Train Running in an Open Section

2006 ◽  
Vol 2006.16 (0) ◽  
pp. 114-115
Author(s):  
Hajime TAKAMI ◽  
Katsuhiro KIKUCHI ◽  
Masanobu IIDA ◽  
Hiroshi MAEKAWA ◽  
Takeshi KURITA ◽  
...  
Keyword(s):  
High Speed ◽  
Low Frequency ◽  
Frequency Noise ◽  
High Speed Train ◽  
Low Frequency Noise ◽  
Open Section

Low frequency noise sources in AlGaN/GaN HEMTs

1999 ◽  
Author(s):  
J. A. Garrido ◽  
F. Calle ◽  
E. Muñoz ◽  
I. Izpura ◽  
J. L. Sánchez-Rojas ◽  
...  
Keyword(s):  
Low Frequency ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Noise Sources ◽  
Gan Hemts

Effect of Ge-Nanoislands on the Low-Frequency Noise in Si/SiOx/Ge Structures

2013 ◽  
Vol 854 ◽  
pp. 21-27 ◽  
Author(s):  
N.P. Garbar ◽  
Valeriya N. Kudina ◽  
V.S. Lysenko ◽  
S.V. Kondratenko ◽  
Yu.N. Kozyrev
Keyword(s):  
High Surface ◽  
Low Frequency ◽  
Noise Model ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Physical Processes ◽  
Noise Sources ◽  
Noise Component ◽  
First Time ◽  
Noise Models

Low-frequency noise of the structures with Ge-nanoclusters of rather high surface density grown on the oxidized silicon surface is investigated for the first time. It was revealed that the 1/f γ noise, where γ is close to unity, is the typical noise component. Nevertheless, the 1/f γ noise sources were found to be distributed nonuniformly upon the oxidized silicon structure with Ge-nanoclusters. The noise features revealed were analyzed in the framework of widely used noise models. However, the models used appeared to be unsuitable to explain the noise behavior of the structures studied. The physical processes that should be allowed for to develop the appropriate noise model are discussed.

LES Predictions of Jet Noise for a Pylon-Mounted Dual Stream Nozzle and Jet Surface Interactions

2016 ◽  
Author(s):  
P. Vogel ◽  
J. Bin ◽  
N. Sinha
Keyword(s):  
Supersonic Jet ◽  
Low Frequency ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Acoustic Source ◽  
Noise Sources ◽  
Surface Time ◽  
Acoustic Source Localization ◽  
Jet Nozzle ◽  
Field Noise

An end-to-end LES/FW-H noise prediction model has been demonstrated and validated with acoustic and flowfield data from a dual stream nozzle with pylon experiment conducted at NASA GRC using their Jet Engine Simulator (JES) geometry. Results show a large region of high turbulent kinetic energy (TKE) in the wake of the pylon. Acoustic Source Localization (ASL) studies using our numerical phased array methodology show this wake region to be the principle location of low frequency noise sources while higher frequency sources occur nearer to the nozzle lips. Numerical simulations have also been conducted on Jet-Surface Interaction (JSI) effects of a supersonic jet exhausting parallel to a finite surface. Time-averaged LES data and far-field noise predictions have been obtained for multiple surface locations as well as for an isolated jet nozzle. For upstream observers located below the surface, results show an increase in low-frequency noise over what was predicted for the isolated nozzle due to JSI effects and decrease in high-frequency noise due to shielding. This was significantly more pronounced for an over-expanded jet than for an under-expanded jet, an effect that was primarily attributed to the shorter core length of the over-expanded jet.

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