K. Koppenhoefer, S.Yushanov, and M.H. McKenna
AltaSim Technologies, LLC, Columbus, Ohio, USA
U.S. Army Engineering Research and Development Center
Aging infrastructure requires frequent inspections to assess their structural integrity. However, the large amount of existing infrastructure, and the distance between these structures present significant challenges to inspectors. Acoustics-based technologies represent a simple, and relatively inexpensive, technique to monitor the integrity of a structure. To develop these techniques, designers ...
C. Peyrega, and D. Jeulin
Center of Mathematical Morphology, Mines ParisTech, Fontainebleau, France
This study is a part of the Silent Wall ANR project, to which the Center of Mathematical Morphology is associated. Its main objective is to build an acoustical and thermal insulating system for buildings, composed of fibrous materials. The material is composed of two phases: the fibrous network and the air surrounding it. At the microscopic scale the absorption of the acoustic wave is mainly due ...
G. C. Martins, P. R. Nunes, J. A. Cordioli
Federal University of Santa Catarina, Florianópolis, SC, Brazil
The use of piezoelectric materials in hearing aid loudspeakers, also called receivers, presents technical and economic advantages such as reducing the number of parts of the system and its manufacturing cost. However, the performance of such systems is still not competitive when compared to traditional electrodynamic loudspeakers. In order to achieve an appropriate performance, one option is to ...
G. Campa and S.M. Camporeale
DIMEG, Politecnico di Bari, Bari, Italy
Modern gas turbines suffer of the phenomenon of combustion instability, also known as “humming”. The main origin of the instability is considered to be related to the interaction between acoustic waves and fluctuations of the heat released by the flame. This paper presents a novel numerical method in which the governing equations of the acoustic waves are coupled with a flame heat ...
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 ...
Alcon Research Ltd., Lake Forest, CA, USA
Anomalous acoustic streaming is observed from sharp edges of vibrating solid bodies in fluids. The streaming velocities can be orders of magnitude higher than expected from the Rayleigh streaming at similar amplitudes of vibrations. Acoustic velocity of a fluid relative to a solid body diverges at a sharp edge giving rise to a localized time-independent body force acting on the fluid. The ...
Modeling of Noise Produced by Offshore Wind Turbines with Different Foundations and Effects on the Marine Environment - new
B. Marmo , I. Roberts 
Xi Engineering Consultants, Edinburgh, Scotland, UK
Vibration produced by offshore wind turbines during their normal operation transmits through the tower into the foundation where it interacts with the surrounding water and is released as noise. The noise produced by offshore wind turbines can be detected by fish and marine mammals and may lead to alteration of their behavior. Given that noise is emitted at the interface between the foundation ...
On The Use of a Diffusion Equation Model for Sound Energy Flow Prediction in Acoustically Coupled Spaces
Y. Jing, and N. Xiang
Rensselaer Polytechnic Institute, Troy, NY, USA
This paper studies sound energy flows through an aperture across two coupled spaces using a diffusion equation model. The so-called double sloped sound energy decay is believed to be caused by the sound energy exchange through the aperture coupling the two rooms. The room diffusion equation is first solved by COMSOL, then the time dependent energy flow is visualized via COMSOL arrow plotting, ...
Using COMSOL to Support a Cost-Effective, Non-Destructive Evaluation Approach for Predicting Bolt Failure in Highway Bridges
A. Elyea, B. Doubek, G. Hubbard, and D. Ozevin
Department of Civil Engineering
University of Illinois at Chicago
The development of a quantitative nondestructive evaluation method, as an alternative to visual inspection, for inspecting pre-tensioned bolts in fracture critical bridges is presented. In order to understand the ultrasonic behavior of a wide variety of bolt geometries used in bridges, numerical models of nine different bolt geometries were developed. The numerical models included the ...
Acoustic Attenuation Performance Of Helicoidal Resonator Due To Distance Change From Different Cross-Sectional Elements Of Cylindrical Duct
Poznań University of Technology, Poznań, Poland
This work presents acoustic attenuation performance of helicoidal resonator due to distance change from different cross-sectional elements of cylindrical duct. The helicoidal resonator properties are described mainly in in infinite long cylindrical duct. For practical applications it is important to know the limits of use of this solution. This paper describes how the helicoidal resonator should ...