Poznan University of Technology, Poland
This paper examines a sound propagation without airflow through circular ducts with spiral element inside. Models are numerically computed in three-dimensions. The spiral element in the duct is a newly analyzed acoustical element, geometrically similar to the well-known Archimedes screw. It can be applied significantly in ducted systems, such as ventilation, air-conditioning and heat ...
Tohoku Institute of Technology
This paper is in Japanese.
N. Nama , R. Barnkob , C. J. Kähler , T. J. Huang , F. Costanzo 
 Department of Engineering Science and Mechanics, Pennsylvania State University, PA, USA
 Institute of Fluid Mechanics and Aerodynamics, Bundeswehr University Munich, Neubiberg, Germany
Introduction - The ability to precisely manipulate fluid and particles at microscales is one of the essential requirements for various lab-on-a-chip applications such as drug diagnostics, chemical synthesis etc. Recently, the nonlinear interaction of surface acoustic waves (SAW) with fluid at microscales has been utilized to achieve this aim. When surface acoustic waves interact with fluid ...
G. C. Martins, P. R. Nunes, J. A. Cordioli
Federal University of Santa Catarina, Florianópolis, SC, Brazil
The use of piezoelectric materials in hearing aid loudspeakers, also called receivers, presents technical and economic advantages such as reducing the number of parts of the system and its manufacturing cost. However, the performance of such systems is still not competitive when compared to traditional electrodynamic loudspeakers. In order to achieve an appropriate performance, one option is to ...
H. Chen , J. Li , S. Xia ,
 Hunan University, Changsha, Hunan, China
 Xi'an Jiaotong University, Xi'an, Shaanxi, China
Introduction In order to understand the detection mechanism of the PZT based nondestructive testing (NDT) technology for interface debonding of CFSTs, numerical simulation on a multi-physical model composed of surface-mounted PZT patches and CFST structural member is established in COMSOL Multiphysics®. The stress propagation process and the electrical signal output of an embedded PZT patch as ...
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.
Modeling and Experimental Verification of the Power Transfer and Thermal Characteristics of Piezoelectric Transformers Subjected to Combined Mechanical and Electrical Loading
S. Tuncdemir, W.M. Bradley
Solid State Ceramics, Williamsport, PA, USA
QorTek, Williamsport, PA, USA
A piezoelectric transformer allows purely mechanical transfer and scaling of electrical energy via simultaneous utilization of both the direct and converse piezoelectric effects. This mechanical energy transfer enables a wide range of functional differences from typical magnetic-based electrical power transformers. Comparing to their electromagnetic counterparts, piezoelectric transformers are ...
Infrasound Assessment of the Roller Compacted Concrete Dam: Case Study of the Portugues Dam in Ponce, PR
H. Diaz-Alvarez , V. P. Chiarito , S. McComas , M. H. McKenna ,
 U.S. Army Engineer Research and Development Center, Vicksburg, MS, USA
The U.S. Army Corps of Engineers is currently investigating the use of infrasound sensors to monitor the health of structures of interest. Infrasound is low-frequency (2-20 Hz) acoustic energy and is capable of propagating many kilometers from the source structure. Large infrastructure, such as dams, bridges, and buildings emit such signals at their natural or driven frequencies of vibration, ...
N. Martaj [1,2], S. Savarese , S. Kouidri , M. M. ALI [4,5]
 EPF Ecole d’ingénieurs, Montpellier, France
 Institut d'Electronique et des Systèmes, Université de Montpellier, Montpellier, France
 Armélio, Les Ulis, Courtabœuf, France
 LIMSI-CNRS, Orsay, France
 UPMC Univ Paris 06, Paris, France
The reduction of energy consumption in the building sector (nearly 40% of the energy consumption in Europe) is a real challenge to achieve the objective of the “2020 European climate and energy package”. In recent years, great interest is observed for the Stirling thermoacoustic machines. Nonlinearities due to the high level of acoustic pressure generate DC flows that are superimposed on the ...
A-S. Moreau, H. Lissek, and R. Boulandet
EPFL-STI-IEL-LEMA, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
In this paper, the underlying concept of electroacoustic absorbers is studied with the help of Comsol Multiphysics® Acoustics Module. Among the different ways to obtain variable acoustic properties on an electroacoustic transducer's voicing face, there is the shunting of the transducer's electrical input. With such shunt devices, the acoustic impedance that the transducer's membrane presents ...