ACOUSTIC-GRAVITY WAVES FROM AN ENERGY SOURCE AT THE GROUND IN AN ISOTHERMAL ATMOSPHERE
RAND CORP SANTA MONICA CA
Pagination or Media Count:
An analysis is given by two different methods--stationary phase and kinematic theory--of the pressure pulse generated by a nuclear explosion near the ground in an isothermal atmosphere. The present study builds upon work reported earlier. The shape of the signal is shown as a function of time at several distances from the source for a fixed altitude, and at several altitudes for a fixed lateral distance. The first signal to arrive at any location is a high-frequency acoustic wave, followed by a low-frequency acoustic-gravity wave. The onset of the latter is marked by a sharp front, or caustic. At any instant after the arrival of the caustic there are three principal frequency components at any location, the lowest of which becomes dominant as time progresses. It is shown how the qualitative features of the flow, as well as the exact location of the caustic, can be obtained from kinematic theory.
- Radiofrequency Wave Propagation