Clemson University, Clemson, SC, USA
Surface acoustic wave (SAW) devices are commonly used as wireless filters, resonators, and sensors. The confinement of acoustic energy near the surface of a piezoelectric substrate in a SAW sensor makes it highly sensitive for discerning surface perturbation. As sensors, SAW devices have the potential to provide a high-performance sensing platform with capabilities of remote and high-temperature ...
R. Christensen ,
 GN ReSound A/S, Copenhagen, Denmark
The vibration of an electrodynamic loudspeaker driver causes a resulting sound pressure. For simple pistonic vibration, there is a simple relationship between the vibration and the sound pressure. For complex vibration patterns, however, different parts of the vibrating surface contribute differently to the sound pressure, depending on the position in which the sound pressure is evaluated. A ...
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 ...
Simulating Acoustic Combustion Chamber Eigenmodes to Facilitate Combustion Stability in Rocket Engines
R. Kaess , J. Braun ,
 Airbus Safran Launchers, Ottobrunn, Germany
Airbus Safran Launchers is the market leader in Space Launch services. Rocket engines are among the most powerful machines that exist. The core of the rocket engine is the combustion chamber where in the case of liquid propellant rocket engines, fuel and oxidizer are injected, mixed and burnt and where, consequently, the energy release takes place. The hot combustion gases are accelerated in a ...
V. Vadde, and B. Lakshmi G
In this paper, we develop and analyze a standard piezoacoustic Tonpilz-transducer model for underwater acoustics in Comsol by addressing the attendant piezoelectric and pressure acoustic multiphysics phenomena. Transducer properties that are studied and characterized are the center frequency, bandwidth, linearity, sensitivity, and noise figure. In an effort to miniaturize the transducer, a ...
J. M. Stauber , B. A. Marmo ,
 Xi Engineering Ltd, Edinburgh, United Kingdom
Tonal noise from wind turbines can have effects on neighboring residences and its emission can result in strong regulatory penalties that can include the closure of wind farms. The authors present a model of a new broadband damping approach where containers filled with EniDamp™, an Advance Particle Damping (APD) material. The containers, so-called APD pods, are magnetically fixed to wind ...
M. Swamy, L. J. van Lier, J. Smeulers
TNO, Delft, The Netherlands
In one of the screw compressor system, designed silencer was not optimal. A great challenge was the large variation in operating conditions, especially the variation of the molecular weight of the gas. There was need to optimize the silencer. This paper describes the acoustic modelling tools to optimize the acoustic performance of the silencer. Optimization steps carried out are based on the ...
D. Neihguk , M. L. Munjal , A. Prasad ,
 Mahindra & Mahindra Ltd, Chennai, India
 Indian Institute of Science, Bangalore, India
Perforated pipes are extensively used to control exhaust noise in automobiles [1-4]. The energy loss associated with the perforations leads to back pressure which needs to be quantified and minimized . An objective approach presented in  is the introduction of friction factor for perforated ducts as a function of the porosity. In this article, the utilization of the CFD Module of COMSOL ...
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 ...
R. S. Hallikar , S. Munshi , M. U. Kumari, K. Padmaraju,
 R. V. College of Engineering, Bengaluru, Karnataka, India
 JNTU Kakinada, Kakinada, Andhra Pradesh, India
This paper concentrates on developing a self-contained cochlea whose performance is at par with natural hearing. The Artificial Basilar Membrane (ABM) design is done in such a manner so as to get a performance similar to the natural hearing. Finite element analysis was done with the help of COMSOL Multiphysics software. Two materials, Polyvinylidene fluoride (PVDF) and lead zirconate titanate ( ...