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Instrumentation requirements for measurement of sonic boom and blast waves—A theoretical study

1968; Elsevier BV; Volume: 7; Issue: 3 Linguagem: Inglês

10.1016/0022-460x(68)90135-1

1095-8568

Malcolm J. Crocker, Louis C. Sutherland,

Geophysics and Sensor Technology

The modifications to an ideal sonic boom and to an ideal blast wave caused by various measuring systems with different frequency response limitations are determined analytically. Measurement systems with low-pass, high-pass, and band-pass frequency response characteristics are considered. The approach adopted is to obtain the Fourier transform of the ideal shock pulse and by using the system frequency-response function to predict the measured time history of the pulse. The measured time histories for each system are computed for various system cut-off frequencies. The computations indicate the effects upon the measured peak overpressure, upon the duration, and upon the impulse of the positive phase and also the apparent finite rise time caused by limitations in the frequency response of the measuring system. Some comparison is made with experimental measurements. “Ringing” of the transducer diaphragm is also examined. Recommendations are made for frequency response requirements for practical air shock measuring systems and in particular it is recommended that a sonic boom measuring system should have a linear frequency response with lower and upper cut-off frequencies of 0·05 and 10,000 Hz, respectively.