Veröffentlichungen und Präsentationen

Hier finden Sie Veröffentlichungen und Präsentationen der weltweit stattfindenden COMSOL-Konferenzen. In diesen präsentieren Ihre Fachkollegen ihre neuesten mit COMSOL Multiphysics entwickelten Produkte und Ideen. Die Forschungsthemen umfassen ein weites Feld von Industrien und Anwendungsbereichen, die von Mechanik und Elektronik über Strömungen bis zur Chemie reichen. Nutzen Sie die Quick Search, um die zu Ihrem Forschungsbereich passenden Präsentationen zu finden.

Wave Carpet Simulation using Coupled Hydro-elastic FEMLAB Model

Ibragimov A., Koola, P.M.
Texas Tech University, Mathematics and Statistics, Lubbock TX, BSI One KBSI Place, East University, TX

Wave Carpet is a novel deep offshore wave-power floating system concept funded by the Office of Naval Research that will have low overall life cycle cost due to an integrated design and be rapidly redeployable. In this paper we numerically model the Wave Carpet motion using a coupled hydro-elastic time-domain solution. The major feature of the mathematical model is the presence of non ...

Numerical Model of a Very Light Jet Cavity

F. Teuma Tsafack, T. Kletschkowski, and D. Sachau
Helmut-Schmidt-University / University of the Federal Armed Forces, Hamburg, Germany

To prepare for the installation of a combined audio-ANC-system for a very light jet (VLJ), a finite element model of the investigated cavity was developed.Both an eigenvalue analysis and a time harmonic analysis were performed. The latter was needed to determine the transfer functions between error sensors and actuators.The simulations were performed using COMSOL Multiphysics. The results of the ...

Linear Water Wave Propagation around Structures

L. Martinelli, and A. Lamberti
Universita di Bologna, Italy

Objective of this contribution is to show how to implement the Mild Slope Equations with COMSOL Multiphysics. These equations are commonly used to study the propagation of waves in harbors. Some interesting features are presented, namely the use of weak terms (used for the modelling of the source term); the evaluation of a smooth phase gradient from the complex dependent variable; a robust ...

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 ...

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.

Lösung eines gekoppelten Konvektions-Diffusions-Problems aus der Akustik

G. Bärwolff
TU Berlin, Inst.f.Math., Berlin

Zur effizienten Beschreibung akustischer Systeme werden oft sogenannte Netzwerkmodelle benutzt. Hierbei wird das Gesamtsystem in einzelne (einfache) Elemente zerteilt, die dann jeweils durch ihr eigenes Übertragungsverhalten charakterisiert sind. Besonders einfach lässt sich dieses Übertragungsverhalten darstellen, wenn zwischen den Elementen nur ebene Wellen ausbreitungsfähig sind.1 In ...

On the Numerical Modeling of Elastic Resonant Acoustic Scatterers

V. Romero-García[1], A. Krynkin[2], J.V. Sánchez-Pérez[1], S. Castiñeira-Ibáñez[3], and L.M. Garcia-Raffi[4]
[1]Centro de Tecnologías Físicas Acústica, Universidad Politécnica de Valencia, Valencia, Spain
[2]School of Computing, Science & Engineering, University of Salford, Salford, United Kingdom
[3]Depto. Física Aplicada, Universidad Politécnica de Valencia, Valencia, Spain
[4]Instituto Universitario de Matemática Pura y Aplicada, Universidad Politécnica de Valencia, Valencia, Spain

The elastic and geometrical properties of Low Density Polyethylene (LDPE) foam are used in this paper to improve the attenuation properties of periodic arrangements of acoustic scatterers known as Sonic Crystals (SCs). A specific recycled profile of LDPE foam is used as elastic-acoustic scatterer. The acoustic spectrum of the single scatterer shows two attenuation peaks in the low frequency ...

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 ...

Comsol’s New Thermoviscous Interface and Computationally Efficient Alternative Formulations for FEM

W. R. Kampinga[1], and Y. H. Wijnant[2]
[1]Reden, Hengelo, Netherlands
[2]University of Twente, Enschede, Netherlands

Three efficient alternatives to the model in COMSOL’s thermoacoustics interface are presented. The higher efficiency of these models are explained from theory and are demonstrated by means of two examples.

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 ...

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