When the blast takes place, there is shock wave generated. This shock wave has the velocity that ranges from hundreds of meters per second to few kilometers per second depending upon the intesity of blast. I want to know the formulation through which the shock wave speed could be calculated. Kindly suggest.
Furthermore, if the blast waves come across or interact with different class of materials, how does the wave speed changes?
The air velocity has been measured in blast waves produced by the detonation of trinitrotoluene charges varying in mass from 30 to 200000 lb. The technique consists essentially of using a high-speed camera to record the displacement of smoke trails formed close to the charge just before detonation. This phenomenon does not occur in the case of the detonation of an explosive with a high oxygen balance, or for a nuclear detonation. The velocity decay within a trynitrotoluene blast wave may be described by the equation V = Vs (1 – βt) exp (– αt) + a ln (1 + βt) fitted to the data by an iterative least-squares procedure. It has been demonstrated that particle trajectories, determined by the smoke tracer technique, may be used to calculate the variations of density, pressure and temperature within the wave, without reference to other measurements.
It is recommended to use a table provided in the reference document UFC-3-340-2 :
https://www.wbdg.org/ffc/dod/unified-facilities-criteria-ufc/ufc-3-340-02
There is no general formula for determining the speed of blast induceed ground vibrations. Because blast waves, the ambient properties (mass and matterial) in which they spread affect the wave speed significantly.
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