Technical Papers and Presentations

Here you will find presentations given at COMSOL Conferences around the globe. The presentations explore the innovative research and products designed by your peers using COMSOL Multiphysics. Research topics span a wide array of industries and application areas, including the electrical, mechanical, fluid, and chemical disciplines. Use the Quick Search to find presentations pertaining to your application area.

Piezoelectric Buzzer Optimization for Micropumps

A. Garcia[1], A. Marcus[1], F. Tejo[1], C. Precker[1], C. Moreira[2]
[1]Universidade Federal de Campina Grande, Campina Grande, PB, Brazil
[2]Instituto Federal de Alagoas, Maceio, AL, Brazil

Piezoelectric buzzers are low cost devices which can be used successfully as actuators in diaphragm-based micro-pumps. The buzzers are piezoelectric wafers (lead-zirconate-titanate-PZT) that are glued on a brass membrane and they are available within different sizes and thicknesses. For the best performance of a diaphragm pump, it is necessary to have a large displacement of the membrane. This ...

Discrete Projection Methods for Incompressible Fluid Flow Problems and Application to a Fluid-structure Interaction Problem

Sautter, J.M.
Mathematisches Institut, Universität Düsseldorf, Germany

Numerical simulations of transient incompressible fluid flow in arbitrary (two- or threedimensional) domains, possibly coupled with other effects, are of great importance in many industrial applications. Discrete projection methods are efficient time integration schemes for incompressible fluid flow simulations. It is shown how the time-dependent Navier-Stokes equations can be implemented ...

Finite Element Simulation of Ultrasound Contrast Agent Behaviour

M. C. Pauzin1,2, S. Mensah1, and J. P. Lefebvre1
1 Laboratoire de Mécanique et d'Acoustique, Marseille, France
2 Aix-Marseille Université, Marseille, France

Experimental studies of Ultrasound Contrast Agents (UCAs) indicate that adherent UCAs are acoustically differentiable from free-floating UCAs. This study aims to create a numerical model of UCAs that can be used to predict how attachment affects their behavior.At first, a simple gas core microbubble is considered. Then an elastic shell is incorporated into the model: the acoustic phenomenon is ...

Sound Attenuation by Hearing Aid Earmold Tubing

M. Herring Jensen
Widex A/S, Vaerloese, Denmark

In this study we model the sound attenuation properties of a hearing aid earmold tube. The model includes thermoviscous acoustic effects and it couples structural vibrations to the external acoustic field. Moreover, the finite element domain is coupled at two boundaries with an electroacoustic model of a hearing aid and an acoustic 2-cc coupler.

Numerical Simulations of Ultrasonic Non Destructive Techniques of Masonry Buildings

S. Carcangiu[1], B. Cannas[1], M. Usai[1], and G. Concu[2]
[1]Department of Electric and Electronic Engineering, Cagliari, Italy
[2]Department of Structural and Infrastructural Engineering and Geomatics, Cagliari, Italy

An experimental program has been developed, with the purpose of evaluating the reliability in building diagnosis and characterization of an integrated analysis of several parameters, associated with acoustic waves propagating through the material. The Direct Transmission Technique has been applied. In this paper we developed a numerical model using the Transient Acoustics-Piezoelectric ...

Evanescent Waves at the Interface Between Ear Canal and Otoacoustic Emission Probe

M. Zebian[1,2], J. Hensel [2], and T. Fedtke[2]
[1]Physikalisch-Technische Bundesanstalt, Braunschweig, Germany
[2]International Graduate School of Metrology, Braunschweig, Germany

Otoacoustic emission (OAE) tests provide an objective examination of the cochlear function. However, the validity of OAE tests is affected negatively by calibration errors. This report sheds light on the evanescent waves arising at the interface between the OAE probe and the ear canal, and analyses the impact of minor eartip modifications on the acoustic length estimation of ear canals, using ...

A Study of the Acoustic Response of Carbon Fiber Reinforced Plastic Plates

J. O'Donnell, and G. McRobbie
University of the West of Scotland
Paisly, United Kingdom

This paper gives an introduction to a continuing study detailing the process and development of using both experimental and Finite Element Analysis to characterise the acoustic response of a Carbon Fiber Reinforced Plastic (CFRP) laminate plate provided by a guitar manufacturer. The results show that there is a strong correlation between both the experimental and simulated data which gives the ...

Electro-acoustic Coupling in Nematic Liquid Crystals

G. Rosi[1], L. Teresi[1], A. DiCarlo[1], and F. dell'Isola[2]
[1]LaMS - Università degli Studi Roma Tre, Roma, Italy
[2]Università degli Studi di Roma "La Sapienza", Roma, Italy

Liquid crystals - as all liquids - are generally modelled as incompressible media. In fact, mass-density changes occurring in these mesophases are minuscule and inconsequential in most regimes of interest. However, liquid crystals exhibit also phenomena that call for a more refined theory. In particular, it is experimentally well established that the Fréedericksz transition - i.e., the sudden ...

Eigenmodes of Photoacoustic T-cells

Baumann, B.1, Kost, B.1, Groninga, H.2, Wolff, M.1, 2
1 University of Applied Sciences Hamburg, Mechanical and Production Engineering
2 PAS-Tech GmbH, Zarrentin

The photoacoustic effect is based on resonant absorption of light by a sample and the transfer of the excitation energy into thermal energy via inelastic collisions of gas molecules. A modulated irradiation of the sample causes periodic pressure variations that can be detected by a microphone and measured using lock-in technique. Photoacoustic spectroscopy finds many applications in the field of ...

A Study of FEMLAB for Modeling High Frequency Ultrasound Scattering by Spherical Objects

Falou, O.1, Kumaradas, J.C.2, Kolios, M.C.3 1 Dept. of Electrical and Computer Engineering, Ryerson University, ON, Canada
2 Dept. of Electrical and Computer Engineering & Dept. of Physics, Ryerson University, ON, Canada
3 Dept. of Physics, Ryerson University, ON, Canada

Analytical solutions to the problem of wave scattering from three dimensional structures such as spheres have been studied extensively in the past. However, these solutions are not flexible enough to be extended to wave scattering from complex geometries. We have developed a finite element model of acoustic wave propagation through spherical structures to solve the problem of highfrequency (20 ...

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