Prediction of noise transmission in a submerged structure by statistical energy analysis

Download
2012
Cavcar Yayladere, Bahar
The aim of this study is to develop a sound transmission model that can be used to predict the vibration and noise levels of a submerged vessel. The noise transmitted from the mechanical vibrations of the hull of a submarine and the turbulent boundary layer excitation on the submarine are investigated. A simplified physical model of the submarine hull including the effects of bulkheads, end enclosures, ring stiffeners and fluid loading due to the interaction of the surrounding medium is presented in the study. An energy approach, i.e., Statistical Energy Analysis (SEA) is used for the analysis because the characterization of the hull of the structure can be done by a very large number of modes over the frequency range of interest and the deterministic analysis methods such as finite element and boundary element methods are limited to low frequency problems. The application consists of the determination of SEA subsystems and the parameters and the utilization of power balance equations to estimate the energy ratio levels of each subsystem to the directly excited subsystem. Through the implementation of SEA method, the sound pressure levels of the hull of the structure are obtained. In terms of military purposes, the sound levels of the submarine compartments are vital in the aspects of the preserving of submarine stealth.

Suggestions

Improvement of finite element model by using sine vibration test results of acommunication satellite
Çekiç, Abdulkadir; Yaman, Yavuz; Department of Aerospace Engineering (2021-2-15)
In this thesis, the vibration analysis of a communication satellite is performed,and the improvementof the finite element model by using vibration test results is presented. First, the satellite finite element model isgenerated using MSC/PATRAN and MSC/NASTRAN commercial software. With the natural frequency and frequency response analysis, the expected frequency values and response amplitudes in accelerometers arecalculated in vibration tests. The results obtained in the vib...
Experimental characterization of a tuned vibration absorber
Aksoy, Tuğrul; Özgen, Gökhan Osman; Acar, Bülent; Gençoğlu, Caner (2016-01-01)
In this paper, experimental characterization studies conducted for a tuned vibration absorber is presented. The tuned vibration absorber has been particularly designed to reduce transverse resonant vibration response of a supported cylinder structure at its dominant two modes. Various testing configurations and techniques have been used such as transmissibility measurements, frequency response measurements, sweep sine testing, impact testing, and random testing. Different testing approaches were needed to e...
Chatter detection using vibrational and acoustic emissions in turning process
Süleyman, Büyükkoçak; Kılıç, Şener; Özer, Mehmet Bülent; Ünver, Hakkı Özgür (null; 2013-09-20)
Chatter vibration is a longstanding problem for machining industry. It lowers both surface finish quality and life of cutting tool. In this study, real time chatter vibration detection system is designed and tested experimentally. A traditional lathe, equipped with two accelerometers placed on cutting tool in two orthogonal coordinates and a microphone, is used for machining a steel rod in face turning operation. During cutting process analog data of accelerometers and microphone is acquired by data acquisi...
Numerical prediction of aft radiation of turbofan tones through exhaust jets
Özyörük, Yusuf (2009-08-07)
This paper describes a numerical methodology for calculating tonal noise propagation and radiation through turbomachinery exhaust ducts, including non-uniform background jet flows. The numerical method is based on solution of the linearized Euler equations directly in the frequency domain, employing a direct, sparse matrix solver in parallel. Acoustic sources are introduced into the computational domain via the perfectly matched layer equations. Various test cases including propagation through infinite duct...
Prediction of ducted diaphragm noise using a stochastic approach with adapted temporal filters
Karban, Ugur; Schram, Christophe; Sovardi, Carlo; Polifke, Wolfgang (SAGE Publications, 2019-01-01)
The noise production by ducted single- and double-diaphragm configurations is simulated using a stochastic noise generation and radiation numerical method. The importance of modeling correctly the anisotropy and temporal de-correlation is discussed, based on numerical results obtained by large eddy simulation. A new temporal filter is proposed, designed to provide the targeted spectral decay of energy in an Eulerian reference frame. An anisotropy correction is implemented using a non-linear model. The acous...
Citation Formats
B. Cavcar Yayladere, “Prediction of noise transmission in a submerged structure by statistical energy analysis,” M.S. - Master of Science, Middle East Technical University, 2012.