Seagate Technology, Bloomington, MN, USA
Ultrasonic based cleaning process, widely used in various industries, mainly utilizes the cavitation effect to achieve contamination removal. For a given set of ultrasonic tank parameters, such as cleaning fluid, temperature, frequency etc, the cavitation effect is largely impacted by the amount of ultrasonic energy. Determining optimal ultrasonic energy level often becomes the key to the ...
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 ...
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 ...
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 ...
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 ...
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 ...
A. Giusti, A. Andreini, B. Facchini, F. Turrini, Ignazio Vitale
Department of Energy Engineering, University of Florence, Florence, Italy
Avio, Turin, Italy
In this work a thermoacoustic analysis of a tubular combustor with an advanced lean injection system is presented. The performed analysis is based on the resolution of the eigenvalue problem related to an inhomogeneous wave equation which includes a source term representing heat release fluctuations (the so called Flame-Transfer-Function, FTF) in the flame region. The effect of the mean flow is ...
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, ...
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 ...