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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.

Design Of Acoustic Metamaterials Based On The Concept Of Dual Transmission Line

A-S.Moreau[1], H.Lissek[1], and F. Bongard[2]
[1]Ecole Polytechnique Fédérale de Lausanne, Switzerland
[2]JAST SA, Antenna Systems, Lausanne, Switzerland

In this context, a one-dimensional acoustic transmission line, exhibiting metamaterial properties, is presented. It is composed of an acoustic waveguide, periodically loaded with membranes having the function of series capacitances, as well as transversally connected open channels (denoted stubs) having the function of shunt inductances. A validation of the transmission line design is made with ...

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.

Optimal Placement of Piezoelectric Plates to Control Multimode Vibrations of Rotating Beam

F. Botta[1], D. Dini[2], S. Gentili[1], G. Cerri[1]
[1]Dipartimento di Ingegneria Meccanica e Industriale, Università degli Studi di Roma Tre, Roma, Italy
[2]Department of Mechanical Engineering, Imperial College London, London, United Kingdom

Turbomachines blades are forced by a load resulting from the interaction with the fluid. The consequent vibrations, and the associated fatigue phenomena, can give catastrophic failures and the reduction of the blades life. It could be increased if damping system are used. The piezoelectric materials has received considerable attention by many researcher for their potential application in the ...

Thermo-Acoustic Analysis of an Advanced Lean Injection System in a Tubular Combustor Configuration

A. Giusti[1], A. Andreini[1], B. Facchini[1], F. Turrini[2], Ignazio Vitale[2]
[1]Department of Energy Engineering, University of Florence, Florence, Italy
[2]Avio, Turin, Italy

In this work a thermoacoustic analysis of a tubular combustor with an advanced lean injection system is presented. The performed analysis is based on the resolution of the eigenvalue problem related to an inhomogeneous wave equation which includes a source term representing heat release fluctuations (the so called Flame-Transfer-Function, FTF) in the flame region. The effect of the mean flow is ...

Modeling Low Frequency Axial Fluid Acoustic Modes in Continuous Loop Piping Systems

E. Gutierrez-Miravete[1], E.R. Marderness[2]
[1]Rensselaer Polytechnic Institute, Hartford, CT, USA
[2]General Dynamics-Electric Boat, Groton, CT, USA

Industrial fluid systems often involve continuous piping loops. These systems consist of varying lengths of pipes and hoses connecting multiple components together. Fluid resonances can detrimentally affect the operation of fluid systems and components. This work used COMSOL to investigate the frequency and mode shapes of axial fluid resonances within a system of piping and components that form ...

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 ...

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 ...

Design of a MEMS Resonator for a Centre Frequency Greater than 26.35 MHz and Temperature Coefficient Frequency Less than 0.5 ppm

S.Manikandan[1], R.Radeep krishna[1]
[1]Kalasalingam University, Department of ECE, Srivilliputtur ,Krishnan koil, Tamil Nadu, India

The variability of the design parameters caused by material properties like thermal conductivity is the major challenge in Micro Electromechanical System (MEMS). In resonator design the basic problem is that the frequency changes with temperature variation and quantitative explanation with respect to this varies. The change can be attributed to the stability in terms of frequency drift in parts ...

Numerical Modelling Of Sound Absorptive Properties Of Double-Porosity Granular Materials

R. Venegas, and O. Umnova
Acoustics Research Centre, University of Salford, Salford, United Kingdom

Granular materials have been conventionally used for acoustic treatment due to their sound absorptive and sound insulating characteristics. An emerging field is the study of acoustical properties of multi-scale porous materials. An example of these is a double-porosity granular material in which the grains are porous themselves. In this work, a computational methodology for modelling this type ...

Modelling the Wall Vibrations of Brass Wind Instruments

V. Chatziioannou, and W. Kausel
Institute of Music Acoustics
University of Music and Performing Arts
Vienna, Austria

The vibration of the walls of brass wind instruments has been a subject of study in the field of musical acoustics throughout the last decades. The amplitude of such vibrations, stimulated by the oscillating air pressure inside the instrument bore, is very small compared to the dimensions of the instrument. However, it has been recently shown that at the flaring regions of the bell of brass ...

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