Modeling of the gas suspension expansion with a large pressure-density ratio

Sadin D.V., Shirokova E.N.
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Modeling of gas-particle suspensions with large pressure and density gradients is of practical interest in the study of volcanic phenomena, explosions at different altitudes, as well as in technogenic problems related to the operation of space technology and the formation of space debris. This work presents numerical and analytical investigations of the expansion of gas suspensions with a high ratio (up to six orders of magnitude) of pressures and densities. For numerical modeling, a high-resolution hybrid large-particle method was employed. Under the conditions considered, the accuracy of the method was confirmed by comparison with asymptotically exact solutions. The study examined the wave and structural characteristics of concentrated gas suspension expansion depending on particle volume fraction, particle size, and initial pressure ratio. It was found that the polytropic index and sound speed in the gas suspension depend not only on temperature but also on pressure and particle concentration. With increasing pressure, both the polytropic index and sound speed rise, while with increasing particle volume fraction they decrease. In the case of an arbitrary discontinuity decay, an unusual effect is observed compared with “pure” gas dynamics: the relative velocity of the mixture in the uniform flow region decreases as the initial pressure increases. This is explained by the nonlinear dependence of the sound speed in a gas-dispersed mixture on pressure. With increasing particle size (Stokes number), the mixture flow splits into gaseous and dispersed components. At the initial moment, the contact discontinuity separating the mixture from the rarefied gas region splits into two contact boundaries: gaseous and dispersed. A practical conclusion is that when the particle size changes by two orders of magnitude, the gas-dynamic parameters of the mixture in the rarefaction wave region and up to the medium interface remain close to each other. During spatial expansion, the initial cylindrical shape of the dispersed medium successively transforms into a cross-section resembling a hexagon. At the next stage of expansion, the particles redistribute to form a bilateral conical structure. Eventually, a dispersed formation close to a spherical shape emerges.

Keywords: modeling, gas suspension, expansion, high pressure-density ratio
Citation in English: Sadin D.V., Shirokova E.N. Modeling of the gas suspension expansion with a large pressure-density ratio // Computer Research and Modeling, 2026, vol. 18, no. 4, pp. 809-821
Citation in English: Sadin D.V., Shirokova E.N. Modeling of the gas suspension expansion with a large pressure-density ratio // Computer Research and Modeling, 2026, vol. 18, no. 4, pp. 809-821
DOI: 10.20537/2076-7633-2026-18-4-809-821
URL: http://crm-en.ics.org.ru/journal/article/3746/
Creative Commons License This work is licensed under a Creative Commons Attribution-NoDerivs 3.0 Unported License.

Copyright © 2026 Sadin D.V., Shirokova E.N.

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