Technical Papers and Presentations

Ici vous trouverez les présentations issues des Conférences COMSOL à travers le monde. Réalisées par des utilisateurs de COMSOL Multiphysics, ces présentations explorent tous les domaines actuels d'innovation. Les applications couvrent pratiquement tous les secteurs industriels et impliquent des phénomènes électriques, mécaniques, fluidiques et chimiques. Utilisez la recherche rapide pour trouver les présentations les plus intéressantes dans votre domaine d'intérêt.

Modeling Acoustic Waveguides for Ear Impedance Measurements

R. Sisto[1], L. Cerini[1], D. Mambro[2], A. Moleti[2], F. Sanjust[1]
[1]INAIL Research, Monteporzio Catone, Italy
[2]Università di Roma, Tor Vergata, Italy

The otoacoustic emissions (OAEs) are acoustic signals emitted by the inner ear as a consequence of the activity of a nonlinear feedback mechanism capable of amplifying the signal near to the hearing threshold level. The otoacoustic emissions can be used as an acoustic imaging of the cochlear functionality. They are used in clinics for screening purposes but due to the extreme variability between ...

Transient Heat Transfer Effects from a Flapping Wing

Lind, R.J., Abedian, B.
Department of Mechanical Engineering Tufts University, Medford, Massachusetts

This presentation is a numerical study of fluid flow around a two-dimensional rigid flapping plate and its effects on the resultant transient heat transfer effects on the solid interface. In this study, a flat inflexible thin plate surrounded by air undergoes sinusoidal angular motion from one end while the other end is kept stationary, simulating a flapping motion. The two-dimensional ...

Simulation and Evaluation of Small High-Frequency Side Scan Sonars Using COMSOL

J. Jonsson[1], E. Edqvist[1], H. Kratz[1], M. Almqvist[2], and G. Thornell[1]
[1]Ångström Space Technology Centre, Uppsala University, Uppsala, Sweden
[2]Department of Measurement Technology and Industrial Electrical Engineering, Lund University, Lund, Sweden

High frequency side-scan sonar, to be fitted on a miniaturized submersible explorer, have been simulated and built. The purpose of this study is to see if COMSOL Multiphysics® can be used to predict the performance of the sonar, especially the beam width, setting the resolution of the system. Four models were created, from simple 2-D geometries to more complex 3-D models. The simulated beam ...

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 ...

Towards a Finite Element Calculation of Acoustical Amplitudes in HID Lamps

B. Baumann[1], M. Wolff[1], J. Hirsch[2], P. Antonis[2], S. Bhosle[3], and R. Valdivia Barrientos[4]
[1]Hamburg University of Applied Sciences, Hamburg, Germany
[2]Philips Lighting, Eindhoven, The Netherlands
[3]LAPLACE, Université de Toulouse and CNRS, Toulouse, France
[4]National Institute of Nuclear Research, Salazar, Ocoyoacac, Mexico

High intensity discharge lamps can experience flickering and even destruction, when operated at high frequency alternating current. The cause of these problems has been identified as acoustic resonances inside the lamp’s are tube. Here, a finite element approach for the calculation of the acoustic response function is described. The developed model does not include the plasma dynamics.

Numerical Shape Optimization of Photoacoustic Sample Cells: First Results

B. Baumann1, B. Kost1, M. Wolff1,2, H. Groninga2, T. Blöß1, and S. Knickrehm1
1Hamburg University of Applied Sciences, Hamburg, Germany
2PAS-Tech GmbH, Zarrentin, Germany

First results in the automatic shape optimization of a photoacoustic sample cell are described. The aim is to maximize the sensor’s signal strength. The approach considers all shapes that can be represented by a number of axis-symmetrical truncated cones which are connected in a continuous way. In addition, the cell is subjected to certain constraints (e.g. the laser beam is not blocked during ...

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 Study on Acoustic Field Generated by Dipole Sources in Noncircular Pipe

H. Zhang, W. Lin, and X. Wang
Chinese Academy of Sciences, Institute of Acoustics, Beijing, China

Acoustical well logging is an important technology for petroleum industry. Calibration and testing of tools in real wells is not feasible because the cost is high and the condition is not controllable. During manufacturing and maintaining, the logging tools are usually tested in a fluid filled circular pipe. The acoustic field in non-circular wells are calculated by using of the PDE mode of ...

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 ...

Computational Acoustic Attenuation Performance of Helicoidal Resonators

W. Lapka
Poznan University of Technology
Poznan, Poland

This paper concerns the problem of obtaining proper acoustic attenuation performance through computations. COMSOL was used to solve acoustics systems with helicoidal resonators in the frequency domain. Based on the studies of insertion and transmission loss of helicoidal resonators, a high consistency between the results obtained by numerical calculations with experimental measurements was ...

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