scholarly journals Reducing underwater radiated noise of a SUBOFF model propelled by a pump-jet without tip clearance: Numerical simulation

2022 ◽  
Vol 243 ◽  
pp. 110277
Author(s):  
Xiuchang Huang ◽  
Shuaikang Shi ◽  
Zhiwei Su ◽  
Wanghao Tang ◽  
Hongxing Hua
Keyword(s):  
Numerical Simulation ◽  
Tip Clearance ◽  
Radiated Noise ◽  
Underwater Radiated Noise

noiseNet: A neural network to predict marine propellers’ underwater radiated noise

2021 ◽  
Vol 236 ◽  
pp. 109542
Author(s):  
Youjiang Wang ◽  
Keqi Wang ◽  
Moustafa Abdel-Maksoud
Keyword(s):  
Neural Network ◽  
Radiated Noise ◽  
Marine Propellers ◽  
Underwater Radiated Noise

Numerical Investigation of Effect of Inlet Distortion on Compressor Flow Field and Stability

2017 ◽  
Author(s):  
HaoGuang Zhang ◽  
Kang An ◽  
Feng Tan ◽  
YanHui Wu ◽  
WuLi Chu
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Total Pressure ◽  
Tip Clearance ◽  
Numerical Work ◽  
Stall Margin ◽  
Numerical Investigations ◽  
Inlet Distortion ◽  
Compressor Rotor ◽  
The Stability

The compressor aerodynamic design is conducted under the condition of clean inlet in general, but a compressor often operates under the condition of inlet distortion in the practical application. It has been proven by a lot of experimental and numerical investigations that inlet distortion can decrease the performance and stability of compressors. The circumferential or radial distorted inlet in mostly numerical investigations is made by changing the total pressure and total temperature in the inlet ring surface of the compressors. In most of inlet distortion experiments, distorted inlets are usually created by using wire net, flashboards, barriers or the generator of rotating distortion. The fashion of generating distorted inlet for experiment is different from that for numerical simulation. Consequently, the flow mechanism of affecting the flow field and stability of a compressor with distorted inlet for experiment is partly different than that for numerical simulation. In the numerical work reported here, the inlet distortion is generated by setting some barriers in the inlet ring surface of an axial subsonic compressor rotor. Two kinds of distorted inlet are investigated to exploring the effect of distorted range on the flow field and stability of the compressor with ten-passage unsteady numerical method. The numerical results show that the inlet distortions not only degrade the total pressure and efficiency of the compressor rotor, but also decrease the stability of the rotor. The larger the range of distorted inlet is, the stronger the adverse effect is. The comprehensive stall margin for the inlet distortion of 24 degrees and 48 degrees of ten-passages is reduced about 3.35% and 5.88% respectively. The detailed analysis of the flow field in the compressor indicates that the blockage resulted from tip clearance leakage vortex (TLV) and the flow separation near the suction surfaces of some blades tip for distorted inlet is more serious than that resulted from TLV for clean inlet. Moreover, the larger the range of distorted inlet is, the larger the range of the blockage is. The analysis of unsteady flow shows that during this process, which is that one rotor blade passes through the region affected by the distorted inlet, the range of the blockage in the rotor passage increases first, then reduces, and increases last.

scholarly journals Multi-sensor integration for an assessment of underwater radiated noise from common vessels in San Francisco Bay

2021 ◽  
Vol 149 (4) ◽  
pp. 2451-2464
Author(s):  
Samantha Cope ◽  
Ellen Hines ◽  
Roger Bland ◽  
Jerry D. Davis ◽  
Brendan Tougher ◽  
...  
Keyword(s):  
San Francisco ◽  
San Francisco Bay ◽  
Sensor Integration ◽  
Radiated Noise ◽  
Underwater Radiated Noise

scholarly journals Review of Legislation on Noise and Vibration Regulations in Merchant Ships

2015 ◽  
Vol 157 (A3) ◽  
pp. 135-144
Keyword(s):  
European Union ◽  
Environmental Impact ◽  
The European Union ◽  
Noise And Vibration ◽  
Radiated Noise ◽  
Underwater Radiated Noise ◽  
Board Ship

"This paper aims to describe the evolution of noise regulations for merchant ships over the last four decades, analysing the most important aspects with respect to crew, passengers and exposed populations in cities, in line with the requirements of the European Union to reduce the environmental impact of transport. The paper also analyses the changes in regulations aimed at not only regulating noise and vibration inside the ship, but also noise emitted to the port and underwater radiated noise. We shall also include Classification Societies, given the importance of their standards in ensuring increasing levels of comfort on board ship."

Mitigation of Underwater Radiated Noise Related to Shipping and Its Impact on Marine Life: A Practical Approach Developed in the Scope of AQUO Project

2017 ◽  
Vol 42 (2) ◽  
pp. 373-387 ◽  
Author(s):  
Christian Audoly ◽  
Tomaso Gaggero ◽  
Eric Baudin ◽  
Thomas Folegot ◽  
Enrico Rizzuto ◽  
...  
Keyword(s):  
Practical Approach ◽  
Radiated Noise ◽  
Marine Life ◽  
Underwater Radiated Noise

Noise Control Decision Process for Marine Vessels

2014 ◽  
Author(s):  
Raymond W. Fischer ◽  
Louis M. Pettit
Keyword(s):  
Marine Mammals ◽  
Noise Control ◽  
Regulatory Body ◽  
Noise Levels ◽  
Radiated Noise ◽  
Underwater Radiated Noise ◽  
Sound Levels ◽  
Airborne Noise ◽  
Control Decision ◽  
Marine Vessels

There is a price to be paid to achieve compliance with the acoustic requirements imposed by regulatory agencies. Acoustic requirements typically appear in ship specifications as airborne and/or underwater radiated noise limits as the need to preclude hearing loss for crew members and the need to control sound levels experienced by marine mammals receive more recognition. Recent changes and additions to regulatory body requirements addressing compartment airborne noise and underwater radiated noise can be found in IMO Resolution MSC.337(91) Annex 1 and Annex 2 which state that IMO Resolution A.468(XII) “Code on Noise Levels Onboard Ships” shall take effect on 1 July 2014 for all SOLAS compliant vessels. Thus the airborne noise levels in compartments and at on-deck work stations onboard as-built ships seeking a SOLAS certificate will need to be measured, and must demonstrate compliance with noise limits stated in paragraph 4.2 of IMO Resolution A.468(XII). IMO “Guidelines for the Reduction of Underwater Noise from Commercial Shipping to Address Adverse Impacts on Marine Life” dated 7 April 2014 and agencies such as ICES and DNV have established guidance and/or criteria for control of underwater radiated noise from vessels, and these too are now commonly appearing in ship specifications. Specifications referencing such criteria typically require that compliance be demonstrated by at-sea testing of underwater radiated noise. Making the correct decisions during the ship design process will minimize costs for noise control and will provide a positive return on investment. The process of how best to comply with noise limits while minimizing costs through optimization of noise control treatments and design approaches is discussed.

Sign in / Sign up

Export Citation Format

Share Document