Presentazioni e Articoli Tecnici

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.

Toward an Evaluation of the Tonal Colouring of the Japanese koto using COMSOL Multiphysics and Acoustics Module

K. Coaldrake[1]
[1]The University of Adelaide, Adelaide City, South Australia, Australia

This paper investigates the potential for a multidisciplinary approach using COMSOL Multiphysics for the evaluation of the tonal colouring of the Japanese koto (13-stringed zither). It uses Ando’s classic acoustic studies (1986; 1996) as a benchmark for the analysis of the natural resonant frequencies and design of the sounding body of the koto. It reports on the development of the model and ...

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 ...

Design of Traveling Wave Ultrasonic Vibration Disk for Nano-particles in Liquid Dispersion

J. Muraoka, and T. Suzuki
Yamagata Research Institute of Technology
Yamagata
Japan

The traveling wave ultrasonic vibration disks for dispersion of particles were designed by using of FEM analysis. The vibration disks are required specific vibration pattern, which contains three nodal lines. The vibration disk thickness was calculated to be matched the resonance frequency of bolted langevin type transducer and the specific vibration pattern. The alignment of the transducer was ...

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 ...

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.

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.

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 ...

Can the Drumhead be Decomposed from Spectra? - An Application for the Chesapeake Bay

K. McIlhany[1], and R. Malek-Madani[2]
[1]Physics Department, United States Naval Academy, Annapolis, MD, USA
[2]Mathematics Department, United States Naval Academy, Annapolis, MD, USA

In 1966, mathematician Mark Kac proposed the question "Can One Hear the Shape of a Drum?" in an article for American Mathematical Monthly. In attempting to resolve the Chesapeake Bay from an eigenfunctional approach, a one-to-one mapping of this famous problem has been identified. The quote above will re-write to "Can One Hear the Shape of a Drum from Multiple Point-Sampled Spectra?". This ...

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 ...

Effects Of The Microstructure Of Fibrous Media On Their Acoustic Properties

C. Peyrega, and D. Jeulin
Center of Mathematical Morphology, Mines ParisTech, Fontainebleau, France

This study is a part of the Silent Wall ANR project, to which the Center of Mathematical Morphology is associated. Its main objective is to build an acoustical and thermal insulating system for buildings, composed of fibrous materials. The material is composed of two phases: the fibrous network and the air surrounding it. At the microscopic scale the absorption of the acoustic wave is mainly due ...

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