58 research outputs found
Numerical investigation of acoustic solitons
Acoustic solitons can be obtained by considering the propagation of large
amplitude sound waves across a set of Helmholtz resonators. The model proposed
by Sugimoto and his coauthors has been validated experimentally in previous
works. Here we examine some of its theoretical properties: low-frequency
regime, balance of energy, stability. We propose also numerical experiments
illustrating typical features of solitary waves
Laser Doppler Velocimetry for Joint Measurements of Acoustic and Mean Flow Velocities : LMS-based Algorithm and CRB Calculation
This paper presents a least mean square (LMS) algorithm for the joint
estimation of acoustic and mean flow velocities from laser doppler velocimetry
(LDV) measurements. The usual algorithms used for measuring with LDV purely
acoustic velocity or mean flow velocity may not be used when the acoustic field
is disturbed by a mean flow component. The LMS-based algorithm allows accurate
estimations of both acoustic and mean flow velocities. The Cram\'er-Rao bound
(CRB) of the associated problem is determined. The variance of the estimators
of both acoustic and mean flow velocities is also given. Simulation results of
this algorithm are compared with the CRB and the comparison leads to validate
this estimator
Observation of edge waves in a two-dimensional Su-Schrieffer-Heeger acoustic network
In this work, we experimentally report the acoustic realization the
two-dimensional (2D) Su-Schrieffer-Heeger (SSH) model in a simple network of
air channels. We analytically study the steady state dynamics of the system
using a set of discrete equations for the acoustic pressure, leading to the 2D
SSH Hamiltonian matrix without using tight binding approximation. By building
an acoustic network operating in audible regime, we experimentally demonstrate
the existence of topological band gap. More supremely, within this band gap we
observe the associated edge waves even though the system is open to free space.
Our results not only experimentally demonstrate topological edge waves in a
zero Berry curvature system but also provide a flexible platform for the study
of topological properties of sound waves
Bright and Gap Solitons in Membrane-Type Acoustic Metamaterials
We study analytically and numerically envelope solitons (bright and gap
solitons) in a one-dimensional, nonlinear acoustic metamaterial, composed of an
air-filled waveguide periodically loaded by clamped elastic plates. Based on
the transmission line approach, we derive a nonlinear dynamical lattice model
which, in the continuum approximation, leads to a nonlinear, dispersive and
dissipative wave equation. Applying the multiple scales perturbation method, we
derive an effective lossy nonlinear Schr\"odinger equation and obtain
analytical expressions for bright and gap solitons. We also perform direct
numerical simulations to study the dissipation-induced dynamics of the bright
and gap solitons. Numerical and analytical results, relying on the analytical
approximations and perturbation theory for solions, are found to be in good
agreement
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