Passive and Active Control of the Radiated Sound Power from a Submarine Excited by Propeller Forces

Merz, Sascha; Kessissoglou, Nicole; Kinns, Roger; Marburg, Steffen

doi:10.5957/josr.57.1.100049

Cited by 37 publications

(19 citation statements)

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“…The coupling condition #1 requires equilibrium of the acoustic pressure and the normal stress at the interface and the coupling condition #2 requires continuity of the velocities of the fluid particles and the structure in the normal direction across the interface . The matrix equations for the coupling conditions #1 and #2, respectively, are given by

{bold-italicf}_{bold-italicf} MathClass-rel= {bold-italicC}_{MathClass-ops f} bold-italicp

bold-italicv MathClass-rel= normali ω {bold-italicC}_{bold-italicf s} bold-italicu

where the coupling matrices are given by

{bold-italicC}_{MathClass-ops f} MathClass-rel= MathClass-op\int {bold N}_{bold s}^{bold-italicT} {bold-italicn N}_{bold-italicf} normald Γ

N f are the BEM basis functions, N s are the FEM basis functions, and Θ is the boundary mass matrix . Substituting the coupling conditions into Equations and leads to the following fully coupled system

([], \begin{matrix} falsenone nonefalsearray \\ arraycenter K - ω^{2} M & arraycenter & arraycenter {- C}_{s f} \\ arraycenter - iω {G C}_{f s} & arraycenter & arraycenter MathClass-opH \end{matrix}) ([], \begin{matrix} falsefalsearray \\ arraycenter u \\ arraycenter p \end{matrix}) MathClass-rel= ([], \begin{matrix} falsefalsearray \\ arraycenter f_{MathClass-ops} \\ arraycenter 0 \end{matrix})

The computation of the coupling matrix C sf is the main interest of this work.…”

Section: Methodsmentioning

confidence: 99%

Structural‐acoustic coupling on non‐conforming meshes with quadratic shape functions

Peters

Marburg

Kessissoglou

2012

Numerical Meth Engineering

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SUMMARY Fully coupled finite element/boundary element models are a popular choice when modelling structures that are submerged in heavy fluids. To achieve coupling of subdomains with non‐conforming discretizations at their common interface, the coupling conditions are usually formulated in a weak sense. The coupling matrices are evaluated by integrating products of piecewise polynomials on independent meshes. The case of interfacing elements with linear shape functions on unrelated meshes has been well covered in the literature. This paper presents a solution to the problem of evaluating the coupling matrix for interfacing elements with quadratic shape functions on unrelated meshes. The isoparametric finite elements have eight nodes (Serendipity) and the discontinuous boundary elements have nine nodes (Lagrange). Results using linear and quadratic shape functions on conforming and non‐conforming meshes are compared for an example of a fluid‐loaded point‐excited sphere. It is shown that the coupling error decreases when quadratic shape functions are used. Copyright © 2012 John Wiley & Sons, Ltd.

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{bold-italicf}_{bold-italicf} MathClass-rel= {bold-italicC}_{MathClass-ops f} bold-italicp

bold-italicv MathClass-rel= normali ω {bold-italicC}_{bold-italicf s} bold-italicu

where the coupling matrices are given by

{bold-italicC}_{MathClass-ops f} MathClass-rel= MathClass-op\int {bold N}_{bold s}^{bold-italicT} {bold-italicn N}_{bold-italicf} normald Γ

([], \begin{matrix} falsenone nonefalsearray \\ arraycenter K - ω^{2} M & arraycenter & arraycenter {- C}_{s f} \\ arraycenter - iω {G C}_{f s} & arraycenter & arraycenter MathClass-opH \end{matrix}) ([], \begin{matrix} falsefalsearray \\ arraycenter u \\ arraycenter p \end{matrix}) MathClass-rel= ([], \begin{matrix} falsefalsearray \\ arraycenter f_{MathClass-ops} \\ arraycenter 0 \end{matrix})

The computation of the coupling matrix C sf is the main interest of this work.…”

Section: Methodsmentioning

confidence: 99%

Structural‐acoustic coupling on non‐conforming meshes with quadratic shape functions

Peters

Marburg

Kessissoglou

2012

Numerical Meth Engineering

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“…After solving Eq. (6) and substituting the solution of the vector p into Eq. (2), we can obtain the solution of vector u.…”

Section: Fem/bem For Acoustic-structure Interactionmentioning

confidence: 99%

“…In Figure 4, 'FE88/FMBE94' denotes that the coupled element FE88/BE94 is used for the numerical calculation, the wideband FMM algorithm is applied to accelerate the product of the matrix-vector in the coupled boundary element Eq. (6). The analytical solution is evaluated every 0.01 Hz up to 100 Hz.…”

Section: Numerical Example: An Elastic Spherical Shell Excited By a Umentioning

confidence: 99%

“…Meanwhile, the boundary element method (BEM) is used to model the sound field to avoid the need to mesh the acoustic domain that is often infinite or semi‐infinite. For the analysis of structural–acoustic interaction problems, researchers have paid much attention on the FEM/BEM coupling approaches , where FEM is used to discretize the structure parts and BEM is used to model the acoustic area. For BEM, the use of continuous linear or quadratic elements is often applied, and alternatives to discontinuous elements with high accuracy have been previously investigated .…”

Section: Introductionmentioning

confidence: 99%

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Structural–acoustic sensitivity analysis of radiated sound power using a finite element/ discontinuous fast multipole boundary element scheme

Chen

Zheng

et al. 2016

Numerical Methods in Fluids

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Summary The complete interaction between the structural domain and the acoustic domain needs to be considered in many engineering problems, especially for the acoustic analysis concerning thin structures immersed in water. This study employs the finite element method to model the structural parts and the fast multipole boundary element method to model the exterior acoustic domain. Discontinuous higher‐order boundary elements are developed for the acoustic domain to achieve higher accuracy in the coupling analysis. Structural–acoustic design sensitivity analysis can provide insights into the effects of design variables on radiated acoustic performance and thus is important to the structural–acoustic design and optimization processes. This study is the first to formulate equations for sound power sensitivity on structural surfaces based on an adjoint operator approach and equations for sound power sensitivity on arbitrary closed surfaces around the radiator based on the direct differentiation approach. The design variables include fluid density, structural density, Poisson's ratio, Young's modulus, and structural shape/size. A numerical example is presented to demonstrate the accuracy and validity of the proposed algorithm. Different types of coupled continuous and discontinuous boundary elements with finite elements are used for the numerical solution, and the performances of the different types of finite element/continuous and discontinuous boundary element coupling are presented and compared in detail. Copyright © 2016 John Wiley & Sons, Ltd.

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“…Studies on the control of submerged vessels using hybrid means are also limited in number and scope. A hybrid control method combining active control with a passive resonance changer was investigated by Merz et al (2013) for the breathing modes of the submerged hull. Attenuation of the acoustic response was achieved with actuators that were tuned such that the natural frequencies of the passive elements were similar to the natural frequencies of the hull.…”

Section: Introductionmentioning

confidence: 99%

Submarine structural and acoustic attenuation

Gangemi

Kanapathipillai

2014

Journal of Vibration and Control

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In this paper, the low frequency vibro-acoustic responses from a submerged hull are attenuated using passive, active, and hybrid control strategies. An analytical model representing a simplified physical model of a submarine hull is developed, including the effects of ring-stiffeners, bulkheads, and external fluid loading. At low frequencies, rotation of the propeller results in discrete tones at the blade passing frequency and its harmonics. The fluctuating forces at the propeller are transmitted through the propulsion system, resulting in excitation of the low frequency hull vibrational modes, which in turn results in a high level of structure-borne radiated noise. In this work tuned vibration absorbers, active vibration control, and hybrid vibration absorbers are used to attenuate the breathing and bending modes of the submerged hull. The control performance of a hybrid vibration absorber is compared to the attenuation achieved using a passive absorber and the control performance of a fully active system. Results show that implementation of the hybrid vibration absorber results in significant attenuation of the structural and acoustic responses of the hull. The hybrid vibration absorber also requires a control force of lower magnitude compared with a fully active control system.

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Passive and Active Control of the Radiated Sound Power from a Submarine Excited by Propeller Forces

Cited by 37 publications

References 0 publications

Structural‐acoustic coupling on non‐conforming meshes with quadratic shape functions

Structural‐acoustic coupling on non‐conforming meshes with quadratic shape functions

Structural–acoustic sensitivity analysis of radiated sound power using a finite element/ discontinuous fast multipole boundary element scheme

Submarine structural and acoustic attenuation

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