T. H. Hanley, H. T. D. Grigg, B. J. Gallacher
Newcastle University, Newcastle-Upon-Tyne, UK
Introducing a disorder into a finite periodic oscillatory system induces the presence of a 'trapped mode': a mode in which the displacement field is localised to the region of the disorder. A main inhibitor to MEMS resonators achieving a high quality (Q) factor is energy radiation through the support to the substrate. The trapped modes present a way to tune this to a minimal value. An initial ...
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 ...
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 ...
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 ...
A. Arevalo , D. Castro , D. Conchouso , I. G. Foulds 
 Computer, Electrical and Mathematical Sciences and Engineering (CEMSE), King Abdullah University of Science and Technology (KAUST), Saudi Arabia
 The University of British Columbia, School of Engineering, Okanagan Campus, Saudi Arabia
For our simulation we used the Piezoelectric Devices interface. The structure was set with (clamped) fix constraint boundaries to both ends. The bottom electrode was set to be the ground for the electrostatic physics and the top electrode was set to be a Terminal with potential of 10V. A parametric sweep study was set to change the geometry, the parameters to change was the hole diameter (Holed) ...
H. Lissek, R. Boulandet, and M. Maugard
Ecole Polytechnique Federale de Lausanne
An \"electroacoustic absorber\" is a loudspeaker, used as an absorber of sound, which acoustic impedance can be varied by electrical means. This can be achieved either by plugging passive shunt electric networks at the loudspeaker terminals (“shunt loudspeakers”) or by feeding back the loudspeaker with a voltage proportional to acoustic quantities, such as sound pressure and diaphragm normal ...
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 ...
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.
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 ...
L. Fromme , J. Waßmuth , D. Wehmeier ,
 Bielefeld University of Applied Sciences, Bielefeld, Germany
The knowledge of the acoustical transfer paths in active noise control systems is very important for the performance of the system. Unfortunately, simulation is challenging since even simple configurations require comprehensive experience in physics and modeling. Two test setups were chosen for basic investigations on modeling, simulation and validation. The first results presented here are ...