Axisymmetric acoustic wave-modes propagating along buried water pipes have been investigated by the method of finite elements and experimentally. High precision dispersion relations are presented in this paper as a function of the geometry, the embedding material and the elastic modulus of the pipes. It is found that at low frequencies the fundamental axisymmetric acoustic mode of the water cyl...

Local helioseismology seeks to probe the near surface regions of the Sun, and in particular of active regions. These are distinguished by their strong magnetic fields, yet current local techniques do not take proper account of this. Here, we first derive appropriate gravito-magneto-acoustic dispersion relations, and then use these to examine how acoustic rays entering regions of strong field sp...

Bulk acoustic wave (BAW) resonators are widely applied in filters and gravimetric sensors for physical or biochemical sensing. In this work, a new architecture of BAW resonator is demonstrated, which introduces a pair of reflection layers onto the top of a thin film bulk acoustic resonator (FBAR) device. The new device can be transformed between type I and type II dispersions by varying the thi...

Low-energy collective electronic excitations exhibiting sound-like linear dispersion have been intensively studied both experimentally and theoretically for a long time. However, coherent acoustic plasmon modes appearing in time-domain measurements are rarely observed due to Landau damping by the single-particle continua. Here we report on the observation of coherent acoustic Dirac plasmon (CAD...

Optical gap solitons, which exist due to a balance of nonlinearity and dispersion due to a Bragg grating, can couple to acoustic waves through electrostriction. This gives rise to a new species of "gap-acoustic" solitons (GASs), for which we find exact analytic solutions. The GAS consists of an optical pulse similar to the optical gap soliton, dressed by an accompanying phonon pulse. Close to t...

A block-structured adaptive mesh refinement (AMR) method is applied to the problem of computing acoustic radiation from an aeroengine intake. The aim is to improve the efficiency of the computation through reduction of computational cells. A parallel implementation of the adaptive mesh refinement algorithm is achieved using message passing interface. It combines a range of 2and 4-order spatial ...

We detail our studies on the transient propagation of coherent acoustic phonons (CAPs) in Mn-doped Cd1–xMnxTe [(Cd,Mn)Te] diluted-magnetic and pure CdTe semiconductors. The CAPs were generated by femtosecond optical pulses and then time-resolved using oneand two-color pump-probe spectroscopy. Intrinsic lifetimes on the order of at least tens of nanoseconds of CAP oscillations were observed in (...

Control of sound in phononic band-gap structures promises novel control and guiding mechanisms. Designs in photonic systems were quickly matched in phononics, and rows of defects in phononic crystals were shown to guide sound waves effectively. The vast majority of work in such phononic guiding has been in the frequency domain, because of the importance of the phononic dispersion relation in go...

The field of topological states in phonon solids have been rapidly developing recent years. This work examined the dispersion a compound Boron Phosphide (BP) with Zinc-Blende structure via first-principle calculation. results show that BP is stable theory and hosts rich signatures its dispersion. Specifically, Weyl quadratic nodal line can be found acoustic branches, triple point contact optica...

The staggered-grid finite-difference (FD) method is widely used in numerical simulation of the wave equation. With stability conditions, grid dispersion often exists because of the discretization of the time and the spatial derivatives in thewave equation. Therefore, suppressing grid dispersion is a key problem for the staggered-grid FD schemes. To reduce the grid dispersion, the traditional me...