In questa sezione troverete i lavori presentati alle Conferenze mondiali COMSOL. Le presentazioni descrivono ricerche e prodotti innovativi progettati con COMSOL Multiphysics da colleghi di tutto il mondo. I temi delle ricerche presentate abbracciano un'ampia gamma di settori produttivi e aree applicative, in ambito elettrico, meccanico, fluidodinamico e chimico. Lo strumento di Ricerca Rapida vi permetterà di trovare le presentazioni che si riferiscono all'area di vostro interesse.

Structured Ultrasonic Metasurfaces

R. C. Thiagarajan
ATOA Scientific Technologies Private Limited
Bangalore, India

Ultrasonic acoustic waves usually encounter interfaces with significant impedance mismatch in practical medical or industrial imaging applications. A transparent interface can help to improve the performance of medical and industrial imaging and overall innovative applications. Similarly, a broadband total reflection interface can help to improve the architectural or transportation barrier ...

Analyzing Muffler Performance Using the Transfer Matrix Method 

K. Andersen
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 ...

Laser-Ultrasonics Wave Generation and Propagation FE Model in Metallic Materials

A. Cavuto[1], G.M. Revel [1], M. Martarelli [2], F. Sopranzetti [2]
[1]Università Politecnica delle Marche, Ancona, Italy
[2]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 ...

Acoustic Wave Propagation in Water Filled Buried Polyethylene Pipes - new

T. Graf[1], T. Gisler[1], P. Sollberger[1], O. Schaelli[1]
[1]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 ...

Simulation of a New PZT Energy Harvester with a Lower Resonance Frequency Using COMSOL Multiphysics® - new

H. Elbahr[1], T. Ali[1,2], A. Badawi[1], S. Sedky[1]
[1]Zewail City of Science and Technology - Cairo, Cairo, Egypt
[2]Cairo University, Cairo, Egypt

Energy harvesting from environmental vibration nowadays is feasible because of natural oscillations like that caused by air or liquid flow and by exhalation or the heartbeat of a human body. This vibration frequency is typically low (in order of less than 1 kHz). Accordingly, low-frequency vibration based energy harvesting systems are an important research topic; these systems can be used for ...

PA Loudspeaker System Design Using Multiphysics Simulation

R. Balistreri [1],
[1] 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.

Prediction and Control of Motorcycle Engine Noise under Combustion Load

N. Bhatia [1], U. Mohite [1],
[1] Mahindra 2 Wheelers, Pune, India

Engine is a major source of noise in motorcycle. Acoustic analysis of a single cylinder motorcycle engine under combustion load is presented. Engine surface acceleration obtained from vibration analysis is used as input for acoustic analysis. Process automation is carried out using java script to interpolate nodal acceleration data on the engine skin and to solve the acoustic model for each ...

Effect of Length and Porosity on the Acoustic Performance of Concentric Tube Resonators

D. Neihguk [1], A. Prasad [1],
[1] 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 ...

COMSOL Analysis of Acoustic Streaming and Microparticle Acoustophoresis

H. Bruus[1], P.B. Muller[1], R. Barnkob[1], M.J.H. Jensen[2]
[1]Technical University of Denmark, Kongens Lyngby, Denmark
[2]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. ...

Prediction of Transformer Core Noise - new

R. Haettel[1], A. Daneryd[1], M. Kavasoglu[1], C. Ploetner[2]
[1]ABB Corporate Research, Västerås, Sweden
[2]ABB Transformers, Varennes, QC, Canada

Today, low noise is a mandatory feature for power transformers to comply with customer specifications and environmental regulations. Therefore, it is crucial to develop sound prediction tools with sufficient accuracy to avoid overkill margins in design and costly modifications after transformer completion. The paper will focus on core noise which is a typical multiphysics phenomenon involving ...