Vincent Gibiat

Learn More
The time domain topological gradient has recently been presented as a promising technique for imaging of complex structures [N. Dominguez, et al., Wave Motion 42 (1) (2005) 31-52], showing results obtained on simulated data. The method relies on the adequate combination of two computed ultrasonic fields, one forward and one adjoint. The adjoint field, that(More)
Extensive use of transfer matrices (TMs) is made in determining the acoustic properties of a duct and in in-duct acoustic propagation models in the automotive industry and for musical acoustics purposes. The experimental apparatuses of classical TM measurement methods feature two measurement heads. Two microphones are flush with the walls of each head. The(More)
We present a theoretical study and experimental results for an acoustic multiscattering one-dimensional system made of cylindrical tubes of different diameters whose lengths follow a Cantor-like structure. Homothetic acoustical features and forbidden bands as well as wave trapping phenomena are reported.
Most musical instruments contain, at their very basis, a continuous vibrating element (string or air column) which can be treated as a one-dimensional system. Its oscillation is obtained either through an initial condition or by means of a continuous energy input through a nonlinear device. In both cases and as a first approach, the excitation can be(More)
Mathematical optimization methods based on the topological sensitivity analysis have been used to develop innovative ultrasonic imaging methods. With a single illumination of the medium, they have proved experimentally to yield a lateral resolution comparable to classical multiple-illumination techniques. As these methods are based on the numerical(More)
This paper presents both a theoretical and an experimental investigation of the influence of the mean flow on the input impedance of a duct. The input impedance of an axisymetrical flow duct is calculated, taking into account the convective effect of a uniform flow, the dissipative effect of a turbulent flow and the radiation in an open jet. Each of these(More)
The effect of self-similarity on acoustic and elastic wave propagation at normal incidence is investigated using Classical Cantor and Fibonacci multilayered structures. They are made of two sorts of orthotropic plies having differently oriented orthotropic axes with respect to the propagation direction. The properties of their transmission coefficient are(More)