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SITAR Résumé de rapport

Project ID: EVK3-CT-2001-00047
Financé au titre de: FP5-EESD
Pays: Sweden

Underwater acoustics modelling sw

The results of this SITAR subtask is computer software for modelling of acoustic scattering from objects submerged in seawater, in particular, objects on the seafloor or buried under it. The software contains modules for forward modelling of such scattering as well as a module for identification of the scattering object by searching values of parameters such as size, shape, orientation or acoustic contrast, such that the model-predicted scattered field matches the experimentally observed data. The parameter search is done by either a differential evolution algorithm (DE) or a genetic algorithm (GA) for non-linear global optimisation, combined with local optimisation with the downhill simplex method.

The software is designed for modelling and analysis of scattering data collected with the emitter and the receivers in bi-static configurations. In the SITAR project, a configuration with a ROV-mounted parametric emitter and a vertical array of receiver hydrophones was used, however the software permits more general experimental configurations. The software contains two independent forward scattering models. The first uses an accurate full-field boundary-integral equation (BIE) method for computing the acoustic field scattered by a 3D object in a layered fluid-solid medium. The second is a fast scattering model based on acoustic ray tracing and kirchhoff's scattering approximation. The fast scattering model is used in the object identification module, while the BIE module is used for assessment of modelling accuracy. The software runs on single-host Linux systems as well as on Linux clusters.

Informations connexes


Ilkka KARASALO, (Senior researcher)
Tél.: +46-855503627
Fax: +46-855503686