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 ...
Design and Simulation of an Orbiting Piezoelectric MEMS Gyroscope Based on Detection of Phase-Shift Signals - new
S. Gorelick, J. R. Dekker, B. Guo, H. Rimminen
 VTT Technical Research Centre of Finland, Espoo, Finland
The feasibility of phase-sensitive detection of angular-rates using bi-directional orbiting piezoresonators suspended by thick annular springs with thin-film aluminium nitride piezoactuators on top of them was investigated. The ring-shaped flexures are more suitable for supporting the orbiting motion due to their angle-dependent spring constant. The response of the orbiting resonators to ...
Application of a Weakly Non-Linear Analysis to the Analysis of Thermoacoustic Combustion Instabilities - new
D. Laera, S. M. Camporeale, G. Campa
Politecnico di Bari, Bari, Italy
Ansaldo Energia, Genoa, Italy
The thermoacoustic combustion instabilities are complex phenomena that may occur in steady flow combustion systems that are aboard of, e.g., rocket engines or gas turbines. The phenomena involve the interaction of chemical reactions with fluid-dynamic and propagation of pressure waves in the combustion chamber. Combustion instabilities may lead to a stable condition (known as “limit-cycle”) ...
F. Berger , T. Hummel , P. Romero , M. Schulze , B. Schuermans , T. Sattelmayer ,
 Lehrstuhl für Thermodynamik, TU München, Germany
 GE Power, Switzerland
Modern gas turbine systems for power generation are prone develop so-called thermosacoustic instabilities in the combustion chamber. Physically, these instabilities emerge as large amplitude pressure oscillations within the combustor, which are caused by constructive feedback interactions between the flame and the combustor's natural acoustic modes. The oscillations disturb the combustion ...
N. Chowdhury, Z. Liao, and L. Zhao
Department of Electrical & Computer Engineering, Ryerson University, Toronto, ON, Canada
Department of Architectural Science, Ryerson University, Toronto, ON, Canada
Acoustic wave propagation due to the breakage or slippage of reinforced wire in water-filled prestressed concrete cylinder pipe (PCCP) attracts interest in non-destructive pipe testing. Current practice of acoustic emission (AE) detection and wire-break related events (WRE) recognition is based on field data analysis. This work deals with the theoretical investigation of WRE signal from ...
A-S.Moreau, H.Lissek, and F. Bongard
Ecole Polytechnique Fédérale de Lausanne, Switzerland
JAST SA, Antenna Systems, Lausanne, Switzerland
In this context, a one-dimensional acoustic transmission line, exhibiting metamaterial properties, is presented. It is composed of an acoustic waveguide, periodically loaded with membranes having the function of series capacitances, as well as transversally connected open channels (denoted stubs) having the function of shunt inductances. A validation of the transmission line design is made ...
S. H. Abadi , A. T. Lim ,
 University of Washington, Bothell, WA, USA
Underwater acoustics is an area that studies the sound propagation in water and the interactions with other objects and water boundaries. There are many technologies available for acoustic exploration of the ocean. Underwater vehicles are robots used in ocean sciences that travel underwater autonomously and can tow a hydrophone as a mobile sensor to record sound. The turbulent flow induced by ...
Qingwei Liu , Hangjie Mo 
 Shanghai Jiao Tong University, Shanghai, China
This paper studies the application of laminate magnetoelectric (ME) material in displacement sensor. We studied the L-L block composite thanks to designed structure by coupling displacement signal with the displacement potential of ME composite. A nonlinear approximation is adapted to modeling magnetostrictive phase and implemented in COMSOL Multiphysics® software. The simulation results ...
R.Christensen, and U. Skov
A compression driver is a certain type of electrodynamic loudspeaker which has a phase plug with slits in front of the diaphragm. The slits are narrow enough that the so-called viscothermal effects are of significant importance. In this paper a 2D axisymmetric finite element model of a commercial compression driver is established where the vibroacoustic behavior can be evaluated. The ...
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 ...