R.Christensen, and U. Skov
A compression driver is a certain type of electrodynamic loudspeaker which has a phase plug with slits in front of the diaphragm. The slits are narrow enough that the so-called viscothermal effects are of significant importance. In this paper a 2D axisymmetric finite element model of a commercial compression driver is established where the vibroacoustic behavior can be evaluated. The ...
Y. Li, T.C. Lieuwen, J. Zhou, H. Cao
Zhengzhou University, Zhengzhou City, Henan Province, China
Georgia Institute of Technology, Atlanta, GA
One can hardly get the exact analytic solution of a full time-dependent convection-diffusion equation, for describing the dynamics of a non-premixed flamelet. The analytic solution of the linearized form with such a model was studied by MATLAB®. And also, a numerical computation was made with the linearization model in COMSOL Multiphysics® software, to provide a perfect accordance with the ...
高阁 , 刘震宇 ,
In order to satisfy the requirements of modern range measuring technology, photoelectric theodolites gradually develop towards lightweight and minitype design. As a consequence, the mobile theodolite is becoming a hot spot recently. New requirements are raised for the theodolite base (Figure1), which is an essential part of photoelectric theodolites. Namely, the eigenfrequencies should be high ...
G. Zhu, E.M. Dede
Toyota Research Institute of North America, Ann Arbor, MI, USA
In previous work, a two-dimensional (2D) model was carried out to simulate the phononic band structure of a phononic crystal with square lattice structure, but this model did not account for the out-of-plane phonon dispersions . In fact, for 2D films used for coating materials, it is more interesting to understand their cross-plane properties. In this work, the phonon dispersion relation of ...
张秀海 , 王琼 , 屈治国 ,
引言 多孔材料能够吸收大量声能且只反射少量声波，因此具有良好的吸声性能而被广泛地用于噪声的控制。梯度多孔材料吸声性能的实验研究已经有所开展，但相应的数值研究却很鲜见。 COMSOL Multiphysics® 的使用 本文分别用3层和6层孔隙度呈等差数列的多孔玻璃丝组合成梯度多孔玻璃丝（图1为由3层不同孔隙度的多孔玻璃丝组成的梯度多孔玻璃丝，空气区域为宽W、高H的矩形，余下区域为多孔玻璃丝区域），并根据 DBM 模型采用 COMSOL Multiphysics® 模拟组合成的梯度多孔玻璃丝的吸声性能。 结果 由图2，梯度多孔玻璃丝（3层）与相同厚度、相同孔隙度普通多孔玻璃丝比较，前者在声音处于低频段情况吸声效果有明显的改善。梯度多孔玻璃丝（3层）和梯度多孔玻璃丝（6层）的吸声系数如图3所示，在 100Hz-400Hz 的低频段，两者吸声系数有较大的误差。 结论 ...
N. R. Mahesh, and P. Nair
SSN College of Engineering
Tamil Nadu, India
Acoustic metamaterials are structured materials of negative mass density or negative bulk-modulus or both of them. Materials are tailored in sub-wavelength dimensions so as to get these negative properties. This paper compares the result of an experimental investigation of acoustic metamaterial with negative bulk-modulus to its COMSOL modeling. The resonance characteristics of single ...
T. Kaufmann, F. Kassubek, D. Pape , M. Lenner
ABB Corporate Research, Baden-Dättwil, Switzerland
Lamb waves are elastic waves propagating in free solid plates. In the case of plates loaded with a fluid, the equations describing these waves have to be modified to include the effects of the fluid. In our work we have tackled this problem using COMSOL Multiphysics®. We have used the two-dimensional plane strain model of the solid mechanics interface to calculate the eigenmodes of the coupled ...
Surface Acoustic Wave Scattering Matrix Evaluation Using COMSOL Multiphysics®: Application to Surface Acoustic Wave Transmission Through 2D Surface Phononic Crystal
S. Yankin[1,2], A. Talbi, V. Preobrazhensky[1,3], P. Pernod, O. Bou Matar, A. Pavlova
 Joint International Laboratory LICS/LEMAC, IEMN UMR CNRS 8520, EC Lille, Villeneuve d'Ascq, France
 Saratov State University, Saratov, Russia
 Wave Research Center, Russian Academy of Sciences, Moscow, Russia
This contribution is dedicated to numerical analysis of SAW propagation though 2D surface phononic crystal (PnC) and FE method is nowadays one of most common tool for such calculation. The device under investigation consists of two dispersive IDT and lattice of ferromagnetic pillars realized on 128°YX LiNbO3. In addition to dispersion curves calculations this work describes the results of ...
V. Chatziioannou, and W. Kausel
Institute of Music Acoustics
University of Music and Performing Arts
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 ...
F. J. Navarro-Brull , P. Poveda , J. Ramis , R. Gómez ,
 Departament de Química Física, Universidad de Alicante, Alicante, Spain
 Departament de Física, Enginyeria de Sistemes i Teoria del Senyal, Universidad de Alicante, Alicante, Spain
Possible drawbacks of microreactors are inefficient reactant mixing due to the predominance of laminar flow and clogging (when solid-forming reactions are performed or solid catalyst suspensions are used). Ultrasound has been successfully implemented not only to prevent these problems but also for its well-known mixing and particle-dispersion effects. Several configurations have been used for ...