Measurements and Simulations of Acoustic Propagation Loss in the Baltic Sea

Between 2002 and 2007 FWG has carried out four sea trials at different locations of the western Baltic Sea. These were BAROC 2002 near Landsort and Gotland and UCAC 2006, VOICE 2006 and UCAC 2007 east of Bornholm. Altogether quite a large number of runs with different configurations of source and receiver and different environmental conditions...

Outdoor sound propagation reference model developed in the European harmonoise project

The Harmonoise reference model has been developed in order to predict long-term average sound levels in road and railway situations that are geometrically relatively simple but physically complex. The present paper describes all steps of calculations with this powerful model which includes several advanced numerical propagation methods to...

Deterring effects of 8-45 kHz tone pulses on harbour seals (Phoca vitulina) in a large pool

The marine aquaculture industry suffers losses due to pinniped attacks which damage net enclosures and fish stocks. Acoustic harassment devices (AHDs) emit loud sounds which are intended to deter pinnipeds from approaching aquaculture enclosures. At present, many AHDs emit sounds in the 8-20 kHz frequency range. It is not known whether sounds of...

Sea bottom parameter estimation by inversion of underwater acoustic sonar data

Inversion for bottom parameters using low frequency reverberation data

Active sonar reverberation returns offer the possibility to invert for geo-acoustic bottom parameters to characterise the underwater environment. We present the results of synthetic inversions of reverberation returs generated with a ray-based reverberation model in which bottom scattering is modelled according to a modified Lambert's rule. The...

Validation of a Broadband Normal-Mode Propagation Model Using Shallow Water Experimental Data

Experimental validation of the twins prediction program for rolling noise. Pt.2: Results

Two extensive measurement campaigns have been carried out to validate the TWINS prediction program for rolling noise, as described in part 1 of this paper. This second part presents the experimental results of vibration and noise during train pass-bys and compares them with predictions from the TWINS program. The model is found to give quite...

Modelling of sediment bottom propagation using ray theory

In particular for shallow water environments, propagation through the sediment bottom is often of much-importance for the propagation in the water column. This mechanism was modelled recently using ray paths in stead of full wave modelling. Generally bottom interaction of sound will occur

The ALMOST PC-model for propagation and reverberation in range dependent environments

The ALMOST PC-rnodel is a propagation and range

Benchmark cases for outdoor sound propagation models

The computational tools available for prediction of sound propagation through the atmosphere have increased dramatically during the past decade. The numerical techniques include analytical solutions for selected index of refraction profiles, ray trace techniques which include interaction with a complex impedance boundary, a Gaussian beam ray...

De onderwater-acoustiek en haar toepassingen