相关论文: Lighthill's theory of sound generation in a non-is…

Low frequency acoustic wave generation is studied taking into account the effect of stratification, inhomogeneity of background velocity profile and temperature fluctuations. It is shown that for the typical parameters of convective storms…

The generation of hydrodynamic radiation in interactions of pulsed proton and laser beams with matter is explored. The beams were directed into a water target and the resulting acoustic signals were recorded with pressure sensitive sensors.…

We consider the propagation of hydromagnetic waves generated by a compact turbulent source in low ionized plasmas, applying the Lighthill theory. We assume the plasma to be isothermal, and adopt a uniform, stationary medium thread by…

Acoustic wave generation by turbulence in the stratified, moist atmosphere is studied. It is shown that in the saturated moist air turbulence in addition to the Lighthill's quadrupole and the dipole sources of sound related to…

The generation of second and third harmonics by an acoustic wave propagating along one dimension in a weakly nonlinear elastic medium that is loaded harmonically in time with frequency $\omega_0$ at a single point in space, is analyzed by…

In a recent letter [Europhys. Lett. 97, 34002 (2012)], random matrix theory is introduced for long-range acoustic propagation in the ocean. The theory is expressed in terms of unitary propagation matrices that represent the scattering…

In this paper, the partial-wave expansion method is applied to describe the difference-frequency pressure generated in a nonlinear scattering of two acoustic waves with an arbitrary wavefront by means of a rigid sphere. Particularly, the…

The bubbles involved in sonochemistry and other applications of cavitation oscillate inertially. A correct estimation of the wave attenuation in such bubbly media requires a realistic estimation of the power dissipated by the oscillation of…

In the present paper, directivity patterns of laser-generated sound in solids are investigated theoretically. Two main approaches to the calculation of directivity patterns of laser-generated sound are discussed for the most important case…

Oceanic pressure measurements, even in very deep water, and atmospheric pressure or seismic records, from anywhere on Earth, contain noise with dominant periods between 3 and 10 seconds, that is believed to be excited by ocean surface…

This work studies the effectiveness of acoustic black holes to generate broadband non-reflective traveling waves using a single excitation source. This is inspired by similar observations in the basilar membrane of the mammalian inner ear.…

We consider linear and nonlinear waves in a stratified hydrostatic fluid within a channel of variable area, under the restriction of one-dimensional flow. We derive a modified version of Riemann's invariant that is related to the wave…

The present contribution investigates the mechanisms of sound generation and propagation in the case of highly-unsteady flows. Based on the linearisation of the isentropic Navier-Stokes equation around a new pathline-averaged base flow, it…

Experiments were performed at a proton accelerator and an infrared laser acility to investigate the sound generation caused by the energy deposition of pulsed particle and laser beams in water. The beams with an energy range of 1 PeV to 400…

Phonon creation inside the horizons of acoustic black holes is investigated using two simple toy models. It is shown that, unlike what occurs in the exterior regions, the spectrum is not thermal. This non-thermality is due to the anomalous…

Sound attenuation in low temperature amorphous solids originates from their disordered structure. However, its detailed mechanism is still being debated. Here we analyze sound attenuation starting directly from the microscopic equations of…

Acoustic signals generated by filamentation of ultrashort TW laser pulses in water are characterized experimentally. Measurements reveal a strong influence of input pulse duration on the shape and intensity of the acoustic wave. Numerical…

We consider the wave equation for sound in a moving fluid with a fourth-order anomalous dispersion relation. The velocity of the fluid is a linear function of position, giving two points in the flow where the fluid velocity matches the…

A cell method is developed, which takes into account the bubble geometry of polyhedral foams, and provides for the generalized Rayleigh-Plesset equation that contains the non-local in time term corresponding to heat relaxation. The…

The structure of the sound waves generated in baryonic gas during the evolution of dark matter halos with masses less than the Jeans mass is calculated. In this case, the source of the gravitational field that creates the wave can be either…