A Loudness Calculation Procedure Applied to Shaped Sonic Booms

The economic viability of a supersonic commercial transport airplane would be much enhanced if it could fly supersonically over land. Efforts to design an airplane to produce a minimized sonic boom at the ground require knowledge of the impact of ,sonic booms on people. Loudness, being a fundamental and well-understood characteristic of human he_zrin9, was chosen as a means of quantifying the magnitude of sonic boom impact on people. This paper describes in detail a procedure that can be "used to calculate the loudness of sortie booms. The procedure is applied to a wide range of sonic booms, both classical N-waves and a variety of other shapes of boom,s. Th.e loudness of N-waves is controlled by overpressure and the assoeiated rise time. The loudness of shaped booms is highly dependent on the characteristics of the initial shock. A corrtpar|son of the calculated lou&tess values indicates that shaped booms may have signifieantly rrduccd loudness relative to N-waves having the same peak oveTpressurr. This result implies that a supersonic traTtsport designed to yield ntinimized sonic booms may be sub.stantially more acceptable than art _tneonstrained design.