scholarly journals Composite cylinder cross section tailoring for radiated noise reduction

1993 ◽  
Vol 94 (3) ◽  
pp. 1839-1839
Author(s):  
Colin P. Ratcliffe ◽  
Roger M. Crane ◽  
Armando L. Santiago
Keyword(s):  
Noise Reduction ◽  
Cross Section ◽  
Composite Cylinder ◽  
Radiated Noise

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.

Radiated Noise Reduction in a Single Cylinder Direct Injection (DI) Naturally Aspirated (NA) Engine

2011 ◽  
Author(s):  
Sudhakara Naidu T ◽  
Chaitanya Krishna Balla ◽  
Chris carlson ◽  
David Hudson
Keyword(s):  
Noise Reduction ◽  
Direct Injection ◽  
Single Cylinder ◽  
Radiated Noise

scholarly journals Layout Method of Damping Material for Gearbox Based on Acoustic Contribution

2019 ◽  
Vol 37 (4) ◽  
pp. 757-766
Author(s):  
Yunong Liu ◽  
Lan Liu ◽  
Geng Liu ◽  
Liyan Wu ◽  
Chao Liu ◽  
...  
Keyword(s):  
Noise Reduction ◽  
Present Method ◽  
Element Model ◽  
Low Noise ◽  
Radiated Noise ◽  
Damping Material ◽  
Plate Area ◽  
Acoustic Contribution ◽  
Reduction Effect ◽  
Damping Materials

In order to realize the low noise design of marine gearbox, a layout method of damping materials for gearbox based on acoustic contribution was proposed. The present method can accurately and effectively determine the additional area of damping materials and achieve greatly the noise reduction effect. Firstly, taking a marine single-stage herringbone gearbox as the object, the finite element/boundary element model for the reducer structure was established. After applying the vibration excitation of the gear system, the radiated noise of each field point was solved. Secondly, by analyzing the acoustic transfer vector (ATV) and modal acoustic contribution (MAC), the surface of the gearbox was partitioned, and the partitioned surface was analyzed by using panel acoustic contribution (PAC). Finally, the damping material was added to the plate area which contributes greatly to the radiated noise, and the effect of the noise reduction under different schemes were compared. The results show that the layout design of damping materials based on the present method can reduce the radiation noise of observation points accurately and effectively in the range of 0~4 000 Hz.

Noise Reduction of Engine Component Covers Using the Finite Element Method

1991 ◽  
Author(s):  
Jayaraman Sivakumar ◽  
Shung H. Sung ◽  
Donald J. Nefske
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Noise Reduction ◽  
Forced Vibration ◽  
Integral Method ◽  
Element Model ◽  
The Finite Element Method ◽  
Structural Modifications ◽  
Radiated Noise ◽  
Engine Component

Abstract Radiated noise from an engine component cover is predicted by using a structural finite element model of the cover to predict its forced vibration response, and then by using the Rayleigh integral method to predict its radiated noise. Applications to evaluate the radiated noise from an engine rocker cover and an engine front cover are presented. Measurements of the radiated noise from actual covers installed on a running engine show the predicted noise reduction due to structural modifications is achieved.

scholarly journals A New Feature Extraction Method for Ship-Radiated Noise Based on Improved CEEMDAN, Normalized Mutual Information and Multiscale Improved Permutation Entropy

Entropy ◽  
2019 ◽  
Vol 21 (6) ◽  
pp. 624 ◽  
Author(s):  
Zhe Chen ◽  
Yaan Li ◽  
Renjie Cao ◽  
Wasiq Ali ◽  
Jing Yu ◽  
...  
Keyword(s):  
Feature Extraction ◽  
Mutual Information ◽  
Noise Reduction ◽  
Extraction Method ◽  
Recognition Rate ◽  
Permutation Entropy ◽  
Feature Extraction Method ◽  
Normalized Mutual Information ◽  
Radiated Noise ◽  
New Feature

Extracting useful features from ship-radiated noise can improve the performance of passive sonar. The entropy feature is an important supplement to existing technologies for ship classification. However, the existing entropy feature extraction methods for ship-radiated noise are less reliable under noisy conditions because they lack noise reduction procedures or are single-scale based. In order to simultaneously solve these problems, a new feature extraction method is proposed based on improved complementary ensemble empirical mode decomposition with adaptive noise (ICEEMDAN), normalized mutual information (norMI), and multiscale improved permutation entropy (MIPE). Firstly, the ICEEMDAN is utilized to obtain a group of intrinsic mode functions (IMFs) from ship-radiated noise. The noise reduction process is then conducted by identifying and eliminating the noise IMFs. Next, the norMI and MIPE of the signal-dominant IMFs are calculated, respectively; and the norMI is used to weigh the corresponding MIPE result. The multi-scale entropy feature is finally defined as the sum of the weighted MIPE results. Experimental results show that the recognition rate of the proposed method achieves 90.67% and 83%, respectively, under noise free and 5 dB conditions, which is much higher than existing entropy feature extraction algorithms. Hence, the proposed method is more reliable and suitable for feature extraction of ship-radiated noise in practice.

Underwater radiated noise reduction technology using sawtooth duct for pumpjet propulsor

2019 ◽  
Vol 188 ◽  
pp. 106228 ◽  
Author(s):  
Denghui Qin ◽  
Guang Pan ◽  
Seongkyu Lee ◽  
Qiaogao Huang ◽  
Yao Shi
Keyword(s):  
Noise Reduction ◽  
Radiated Noise ◽  
Underwater Radiated Noise

scholarly journals Biomimetic optimization research on wind noise reduction of an asymmetric cross-section bar

SpringerPlus ◽  
2016 ◽  
Vol 5 (1) ◽  
Author(s):  
Yingchao Zhang ◽  
Weijiang Meng ◽  
Bing Fan ◽  
Wenhui Tang
Keyword(s):  
Noise Reduction ◽  
Cross Section ◽  
Wind Noise ◽  
Wind Noise Reduction
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