A Significant Single Quantity that Typifies a Sonic Bang

Abstract

The paper introduces the concept of the characteristic overpressure, defined as 4I/T, where I is the maximum impulse, that is, the maximum value of the running integral of the overpressure with respect to time, and T is the signature interval, that is, the time interval between the onset of the first shock and the onset of the last shock in the signature. The characteristic overpressure is considered to be a significant quantity, particularly in regard to the effect of sonic bangs on structures. This is illustrated by the collapse that is achieved when the results of Crocker and Hudson are presented in a manner employing the characteristic overpressure. Finally, the characteristic overpressure is shown to lead to a particularly simple engineering formula for the dynamic magnification factor as a function of the product of the natural frequency of a structure and the signature interval.