NASA Marshall Space Flight Center / Jacobs ESSSA Group, Huntsville, AL, USA
Combustion instability in solid rocket motors and liquid engines has long been a subject of concern. Recent advances in energy based modeling of combustion instabilities require accurate determination of acoustic frequencies and mode-shapes. Of particular interest is the acoustic mean flow interactions within the converging section of a rocket nozzle, where gradients of pressure, density, and ...
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 ...
A. Daneryd, D. Ericsson
ABB Corporate Research, Västerås, Sweden
COMSOL AB, Stockholm, Sweden
For certain classes of scientific and technical computations the cloud may offer easily accessible, scalable, and affordable gigantic computing power. A power that for these classes may lead to a step change in model and analysis complexity compared to what is feasible with dedicated clusters and similar networked solutions. Acoustics with or without interaction with coupled physics fields ...
Poznan University of Technology
This paper concerns the problem of obtaining proper acoustic attenuation performance through computations. COMSOL was used to solve acoustics systems with helicoidal resonators in the frequency domain. Based on the studies of insertion and transmission loss of helicoidal resonators, a high consistency between the results obtained by numerical calculations with experimental measurements was ...
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 ...
S. De Paolis, F. Lionetto, and A. Maffezzoli
Department of Innovation Engineering, University of Salento, Lecce, Italy
Finite element analysis has been used to model the ultrasonic wave propagation both in a custom made transducer and in the tested polymer sample. The model consists of acoustic (passive elements) and electroacoustic (active elements) transmission lines. The simulation of the acoustic propagation accounts for the interaction between the transducer and the materials in the buffer rods, and the ...
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 ...
W. R. Kampinga, and Y. H. Wijnant
Reden, Hengelo, Netherlands
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.
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 ...