The possibility of observing acoustic-wave amplification made possible through the heating of neutral particles by electrons in a weakly ionized gas has received some recent attention. -4 The idea is that an existing sound wave, by inducing a space-.time variation in the electron density, would create an acoustic source, thereby generating a wave that interferes constructively with the original...

Introduction Thermoacoustic wave-generators are usually designed and optimized using software tools [1, 2] based on the linear thermoacoustic theory. These tools enable to predict the operating point of a thermoacoustic engine from the balance between the thermoacoustic amplification process and the numerous nonlinear effects saturating wave amplitude growth, the latter effects being very diffi...

We report, for the first time, on the observation of the acoustoelectric amplification of the quality factor in thicknessmode gallium nitride micromechanical filters. Acoustoelectric amplification, which is most effective in piezoelectric semiconductors, occurs when charge carriers drift under the influence of an applied electric field with a velocity higher than that of the acoustic wave, thus...

Resonant and acoustic wave devices have been researched for several decades for application in the gravimetric sensing of a variety of biological and chemical analytes. These devices operate by coupling the measurand (e.g. analyte adsorption) as a modulation in the physical properties of the acoustic wave (e.g. resonant frequency, acoustic velocity, dissipation) that can then be correlated with...

This paper concerns with the modeling and construction of a fifth order method for two dimensional acoustic wave equation in heterogenous media. The method is based on a standard discretization of the problem on smooth regions and a nonstandard method for nonsmooth regions. The construction of the nonstandard method is based on the special treatment of the interface using suitable jump conditio...

An experimental investigation was conducted to examine acoustic receptivity and subsequent boundary-layer instability evolution for a Blasius boundary layer formed on a flat plate in the presence of two-dimensional (2-D) and oblique (3-D) surface waviness. The effect of the non-localized surface roughness geometry and acoustic wave amplitude on the receptivity process was explored. The surface ...