T. Graf, T. Gisler, P. Sollberger, O. Schaelli
School of Engineering and Architecture, Lucerne University, Horw, Switzerland
Axisymmetric acoustic waves propagating along buried water pipes have been investigated by FEM and experimentally. Universal dispersion relations of the fundamental mode were obtained as a function of the standard dimension ratio SDR and of the material surrounding the pipe (soil, air). At low frequency there exists little dispersion and the “dc” phase velocity of the leak noise is independent ...
Dinex Emission Technology A/S, Middelfart, Denmark
Exhaust noise must meet legislation targets, customer expectations and cost reduction which call for design optimization of the exhaust systems in the design phase. One solution is to use 3 dimensional linear pressure acoustics and calculate the transfer matrix of the muffler. The transfer matrix is the basis for calculating either the insertion loss or transmission loss of a muffler. The 3D ...
H. Bruus, P.B. Muller, R. Barnkob, M.J.H. Jensen
Technical University of Denmark, Kongens Lyngby, Denmark
COMSOL, Kongens Lyngby, Denmark
We have simulated the ultrasound-induced acoustophoretic motion of microparticles suspended in an aqueous solution. The full first-order thermoviscous acoustics equations have been implented on a rectangular microfluidic 2D domain excited with an ultrasound field tuned to resonance near 2 MHz. The micrometer-thin but crucial viscous boundary layers at the rigid walls have been fully resolved. ...
A. Cavuto, G.M. Revel , M. Martarelli , F. Sopranzetti 
Università Politecnica delle Marche, Ancona, Italy
Università e-Campus, Novedrate (CO), Italy
A 2D axisymmetric model was considered in order to evaluate the propagation paths of the ultrasonic waves generated inside an aluminum plate sample due to a rapid thermal expansion produced by laser pulse. Laser Doppler Vibrometer is used to experimentally validate the numerical results of the wave propagation in the material. The presented numerical model is able to identify directivity ...
V. Pavelko, I. Pavelko, M. Smolyaninovs, H. Pffeifer, M. Wevers
Riga Technical University, Riga, Latvia
Catholic University Leuven, Leuven, Belgium
A problem of damage prediction in aircraft structure and its non-destructive evaluation is very important for aircraft structural health assessment. The analysis of the features of direct impact of thin-walled laminate component of aircraft was performed by COMSOL Multiphysics software. Mainly the GFRC and CFRC laminates were selected in form either thin separate plate or sandwich structure. The ...
D. Neihguk , A. Prasad ,
 Mahindra & Mahindra Ltd., Chennai, India
The acoustic performance of an acoustically short Concentric Tube Resonator (CTR) is investigated to find an optimum porosity for a given length to diameter ratio. The study is motivated by the following practical difficulties encountered in automotive exhaust noise control: 1. Increasing trend of downsized engine and increase in power to weight ratio of engine for better fuel economy. 2. The ...
Simulation of Acoustic Energy Harvesting Using Piezoelectric Plates in a Quarter-Wavelength Straight-Tube Resonator
B. Li, J.H. You
Southern Methodist University, Dallas, TX, USA
An acoustic energy harvesting mechanism at low frequency (~200 Hz) using lead zirconate titanate (PZT) piezoelectric cantilever plates placed inside a quarter-wavelength straight-tube resonator has been studied using COMSOL Multiphysics 4.3 and compared with experimental data. When the tube resonator is excited by an incident wave at its acoustic eigenfrequency, an amplified acoustic resonant ...
E. Gutierrez-Miravete, W. L. Saunders II, K. Pendley
Rensselaer at Hartford, Hartford, CT, USA
General Dynamics Electric Boat, Groton, CT, USA
United Technologies - Pratt & Whitney, East Hartford, CT, USA
The determination of the modes of vibration of Functionally Graded-Metal-Ceramic Composite plates is important in practice in order to prevent undesired resonances in structural components. This paper describes the application of COMSOL Multiphysics® software for the determination of the modes of vibration of Aluminum A356-T6Alloy-ZrO2 FG-MCC square plates.
R. Jiang, L. Mei, X. Liu, H. Li, Q. Zhang
Department of Electrical Engineering, Materials Research Institute, Pennsylvania State University, University Park, PA, USA
Department of Technical Services, China Oilfield Services Limited, Yanshan, Hebei, China
Logging-while-drilling (LWD) acoustic transducers provide real-time data about the geologic and geophysical properties of the borehole that ensure safety margins and optimize completion. It is important to understand what causes the different resonance modes in the transmitter and obtain relevant acoustic response information to assist new designs and field applications of the transmitter. ...
R. Balistreri ,
 QSC Audio Products, LLC., Costa Mesa, CA, USA
This paper utilizes lumped circuits equivalent and pressure acoustics to simulate the behavior of a PA loudspeaker in order to improve its design.