Akustiskt foder, användning av ett foder samt sätt att framställa ett akustiskt foder

摘要

The present invention relates to an acoustic liner ( 1 ) arranged to attenuate sound. The acoustic liner ( 1 ) comprises a top sheet ( 5 ) having substantially linear characteristics and a liner core ( 2 ) or cavity. The top sheet ( 5 ) comprises a layer ( 3 ) of a metallic foam. The invention also relates to the use of said acoustic liner in a hot stream environment such as the outlet of an aircraft engine, and to the manufacture of an acoustic liner.