In principle it is possible to determine a sound field from measurements of the sound pressure at a finite number of positions. The objective of the project has been to investigate inverse calculations in connection with source reconstruction. The inverse process is normally a reconstruction process, ie the task is to determine the sound source that has generated a given sound field from observations of the sound field. When a sound source is reconstructed, that is, when the physical quantities pressure and normal velocity are known everywhere on the surface, it is possible to calculate the sound field surrounding the sound source. Afterwards, modifications of the sound source can be simulated, and the influence on the radiated sound field is immediately observed. The major problem with inverse methods is to achieve a stable solution, that is, to identify the vibrational pattern of the surface of the source from measurements of the sound field in the vicinity of the source and make sure that it is not highly sensitive to unavoidable measurement errors. If care is not taken, noise will pollute the sound field measurements, and a meaningless vibration pattern on the surface of the source is obtained. Thus, it is extremely important to consider different techniques in order to find one that provides a stable solution.
|Effective start/end date||01/02/1997 → …|