Aerodynamics of stratovolcanoes during multiphase processes
Pyroclastic density currents (PDCs) are gas-particle flows generated during explosive eruptions, which are often erupted over the flanks of stratovolcanoes. These volcanoes may have different shapes, which can affect the flow aerodynamics and hence the depositional processes. Here, multiphase numeri...
| Autores: | , , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2012 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/77279 |
| Acceso en línea: | http://hdl.handle.net/10261/77279 |
| Access Level: | acceso abierto |
| Palabra clave: | Aerodynamics Boundary layer pyroclastic density current stratovolcano wake region |
| Sumario: | Pyroclastic density currents (PDCs) are gas-particle flows generated during explosive eruptions, which are often erupted over the flanks of stratovolcanoes. These volcanoes may have different shapes, which can affect the flow aerodynamics and hence the depositional processes. Here, multiphase numerical simulations are carried out in order to define semiquantitative relationships among the PDC behavior, particle response, and deposit formation. Three stratovolcano shapes are used: straight, convex and concave, and, by means of numerical simulations, their effects both on the flow structure and depositional processes are highlighted. The current starts moving as a homogeneous flow, and then it rapidly evolves to a turbulent boundary layer moving in contact with the ground, overlaid by a companion wake region. Results show that thin boundary layers produce thick deposits of massive layers, whereas thick boundary layers produce thin laminated deposits. Moreover, concave wake regions would produce thick massive deposits of fine ash, whereas convex wake regions would produce thin ash deposits. Copyright 2012 by the American Geophysical Union. |
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