Abstract: The unsteady high-velocity flows formed in a magmatic melt under decompression and accompanied by phase transitions determine the dynamics and structure of eruptions of explosive volcanic systems and are related to the multi-parametric and interrelated processes. Their investigation was carried out on the base of multi-phase mathematical model which includes the full system of kinetics equations. Numerical analysis of a magma state dynamics has shown that the bubble dynamics in the cavitating melt takes a collective character and that the diffusion of dissolved gas from a melt plays the key role in the formation of decompression waves. Two cases were distinguished: one for which the diffusion flux determines only the nucleation process (the gas mass inside the bubbles is practically permanent) and another one where this restriction is omitted. In the first case, the decompression wave front takes a classical smooth form (approximately 100 m wide). In the second case, the decompression wave structure and the melt state behind the saturation front turn out to be principally different. The jumps in the mass velocity and viscosity practically left out the pressure inside the cavitation bubbles unchanged for a long time in spite of their growth where intense gas diffusion is observed. It was shown that, if nuclei density was increased at the expense of micro-crystallites, a wave precursor and the system of discrete zones of saturation in its field were formed. The results of the experimental simulation of the structure of the gas saturated flow erupted from a channel and of the effect of magmatic “bombs” flux formation are presented.

Cite: Kedrinskii V.K. , Kazuoyshi T.
Bubbly Magma State Dynamics at Explosive Character of Decompression
Monography chapter Shock Wave Science and Technology Reference Library. – Springer-Verlag., 2013. – Т.8. – C.363-392. – ISBN 9783642342967. DOI: 10.1007/978-3-642-34297-4 OpenAlex

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W621568752

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