Abstract:

The last decade has seen a revived interest in the study of sonic booms; this is due to an upcoming new breed of supersonic passenger aircraft along with a heightened awareness of marine environmental issues. Sonic boom noise penetrating into a flat, homogeneous ocean is a topic several researchers have already addressed. The primary goal of the authors' research is to study the effects of realistic ocean features on noise penetration. These features include a wavy ocean surface and bubbles near the surface. This presentation will focus on a wavy ocean surface, specifically on somewhat complex surface profiles and on sonic boom effective wavelength/ocean wavelength comparisons. Results using finite difference simulations indicate that a somewhat complex wavy ocean surface profile slightly augments the underwater pressure field (as compared to a flat surface); this result was also found when studying simple surface profiles. Some of the trends observed, however, were not as obvious as seen when studying the simple surface profile. This prompted a study on how the sonic boom effective wavelength compared to the ocean wavelength affects the amount of augmentation to the underwater pressure field. [Work supported by the NASA Langley Research Center.]