Abstract:

Robert W. Young has made many contributions to our understanding of how sound can get transmitted from air to water. One important contribution is Bob's measurements of sonic boom noise penetration into the ocean from supersonic airplanes [J. Acoust. Soc. Am. 44, 392 (1968)]. Bob's last words in this paper were ``I would voice the hope that this experimental evidence will inspire some further theorizing to explain the observations.'' Now almost 30 years after this statement, some of us are still theorizing. The present paper gives a quick overview of the state of knowledge in sonic boom penetration into the ocean and introduces a new boundary element method (BEM) approach to solving the problem of evanescent sound penetrating the ocean surface. The method is based on a mesh made from discretizing the surface of the air--water interface. Perhaps along with analytical formulations, finite difference simulations, and other experimental observations already available for determining the sonic boom noise penetration into the ocean, such new BEM simulations will help us answer the questions which Bob Young has posed. [Work supported by NASA Langley Research Center.]