Publications

2012

• A low frequency model for acoustic propagation in a 2D flow duct: numerical computation
  
  • Joubert Lauris
  • Joly Patrick
  Communications in Computational Physics, Global Science Press, 2012, 11 (2), pp.508-524. In this paper we study a low frequency model for acoustic propagation in a 2D flow duct. For some Mach profile flow, we are able to give a well-posedness theorem. Its proof relies on a quasi-explicit expression of the solution which provides us an efficient numerical method. We give and comment numerical results for particular linear, tangent and quadratic profiles. Finally, we give a numerical validation of our asymptotic model.
• Giens 2011
  
  • Bonnet Marc
  • Cornuault Christian
  • Pagano Stéphane
  , 2012.
• Application of the multi-level time-harmonic fast multipole BEM to 3-D visco-elastodynamics
  
  • Grasso Eva
  • Chaillat Stéphanie
  • Bonnet Marc
  • Semblat Jean-François
  Engineering Analysis with Boundary Elements, Elsevier, 2012, 36, pp.744-758. This article extends previous work by the authors on the single- and multi-domain time-harmonic elastodynamic multi-level fast multipole BEM formulations to the case of weakly dissipative viscoelastic media. The underlying boundary integral equation and fast multipole formulations are formally identical to that of elastodynamics, except that the wavenumbers are complex-valued due to attenuation. Attention is focused on evaluating the multipole decomposition of the viscoelastodynamic fundamental solution. A damping-dependent modification of the selection rule for the multipole truncation parameter, required by the presence of complex wavenumbers, is proposed. It is empirically adjusted so as to maintain a constant accuracy over the damping range of interest in the approximation of the fundamental solution, and validated on numerical tests focusing on the evaluation of the latter. The proposed modification is then assessed on 3D single-region and multi-region visco-elastodynamic examples for which exact solutions are known. Finally, the multi-region formulation is applied to the problem of a wave propagating in a semi-infinite medium with a lossy semi-spherical inclusion (seismic wave in alluvial basin). These examples involve problem sizes of up to about $3\,10^{5}$ boundary unknowns. (10.1016/j.enganabound.2011.11.015)
  DOI : 10.1016/j.enganabound.2011.11.015