ATTENUATION OF WEAK SHOCK-WAVES ALONG PSEUDO-PERFORATED WALLS

Citation
A. Sasoh et al., ATTENUATION OF WEAK SHOCK-WAVES ALONG PSEUDO-PERFORATED WALLS, Shock waves, 8(3), 1998, pp. 149-159
Citations number
22
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Mechanics
Journal title
ISSN journal
0938-1287
Volume
8
Issue
3
Year of publication
1998
Pages
149 - 159
Database
ISI
SICI code
0938-1287(1998)8:3<149:AOWSAP>2.0.ZU;2-C
Abstract
In order to attenuate weak shock waves in ducts, effects of pseudo-per forated walls were investigated. Pseudo-perforated walls are defined a s wall perforations having a closed cavity behind it. Shock wave diffr action and reflection created by these perforations were visualized in a shock tube by using holographic interferometer, and also by numeric al simulation. Along the pseudo-perforated wall, an incident shock wav e attenuates and eventually turns into a sound wave. Due to complex in teractions of the incident shock wave with the perforations, the overp ressure behind it becomes non-uniform and its peak value can locally e xceed that behind the undisturbed incident shock wave. However: its pr essure gradient monotonically decreases with the shock wave propagatio n. Effects of these pseudo-perforated walls on the attenuation of weak shock waves generated in high speed train tunnels were studied in a 1 /250-scaled train tunnel simulator. It is concluded that in order to a chieve a practically effective suppression of the tunnel sonic boom th e length of the pseudo-perforation section should he sufficiently long .