Results 151 to 160 of about 624,031 (203)

Pyroclastic density currents: state of the art and perspectives

Journal of Volcanology and Geothermal Research, 2014
Pyroclastic density currents (PDCs) are mixtures of two components, namely solid particles and fluid (gas) phase. They macroscopically behave as dense, multiphase gravity currents (flowing pyroclastic mixtures of particles and gas) immersed in a less dense, almost isotropic fluid (the atmosphere).
SULPIZIO, ROBERTO, DELLINO, Pierfrancesco, Doronzo DM, Sarocchi D.   +3 more
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A fast, calibrated model for pyroclastic density currents kinematics and hazard

Journal of Volcanology and Geothermal Research, 2016
Abstract Multiphase flow models represent valuable tools for the study of the complex, non-equilibrium dynamics of pyroclastic density currents. Particle sedimentation, flow stratification and rheological changes, depending on the flow regime, interaction with topographic obstacles, turbulent air entrainment, buoyancy reversal, and other complex ...
Ongaro, Tomaso Esposti, ORSUCCI, SIMONE, CORNOLTI, FULVIO   +2 more
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Thermobarometry, vesicularity and microlite populations in pyroclastic density current deposits from the last 4500 years of activity at Galeras, Colombia

Journal of Volcanology and Geothermal Research, 2022
L. Gomez, C. Shaw, B. Pulgarín, S. Castilla, D. Palechor   +4 more
semanticscholar   +1 more source

Effects of flow density on the dynamics of dilute pyroclastic density currents

Journal of Volcanology and Geothermal Research, 2004
Abstract Dilute turbulent pyroclastic density currents may have densities as large as 10–100 kg m −3 . Laboratory experiments using dense gases show that for such currents, the speed of the head of the current depends on the density difference between the current and the surrounding air in a complex way.
Sarah E. Nield, Andrew W. Woods
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Aeromechanic analysis of pyroclastic density currents past a building

Bulletin of Volcanology, 2013
An aeromechanic analysis of pyroclastic density currents (PDCs) past a building is carried out on the results of a computer simulation. The analysis shows that PDCs strongly interact with buildings, resulting in turbulent boundary layer separation and recirculation.
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Hazards from pyroclastic density currents at Mt. Etna (Italy)

Journal of Volcanology and Geothermal Research, 2009
Abstract Despite the recent recognition of Mount Etna as a periodically violently explosive volcano, the hazards from various types of pyroclastic density currents (PDCs) have until now received virtually no attention at this volcano. Large-scale pyroclastic flows last occurred during the caldera-forming Ellittico eruptions, 15–16 ka ago, and the ...
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Flow and sedimentation of pyroclastic density currents

2015
Our Earth is a living Planet in which rocks are exhumed at the surface, and subjected to erosion, transport and deposition. Pyroclastic density currents (PDCs) concentrate all these steps in a single phenomenon. During explosive volcanic eruptions, rock fragments known as pyroclasts are ejected from the inside of the Earth to the surface. They can then
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Pyroclastic density currents at Ruapehu volcano; New Zealand

2016
Pyroclastic density currents (PDCs) are hazardous mixtures of volcanic particles and gas that travel along the flanks of a volcano due to a higher bulk density than the surrounding atmosphere. Understanding the frequencies, magnitudes, and different PDC generation and transport processes is essential for understanding the PDC hazard.
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Dispersal and air entrainment in unconfined dilute pyroclastic density currents

Bulletin of Volcanology, 2014
Unconfined scaled laboratory experiments show that 3D structures control the behavior of dilute pyroclastic density currents (PDCs) during and after liftoff. Experiments comprise heated and ambient temperature 20 μm talc powder turbulently suspended in air to form density currents within an unobstructed 8.5 × 6 × 2.6-m chamber.
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Dynamics and hazards of stratified pyroclastic density currents

2014
In the context of a study on pyroclastic flow hazards in caldera settings, we have analyzed the role of particle sedimentation and stratification on the kinematics of particle-driven gravity currents. By means of a two-dimensional multiphase flow numerical model we have simulated the propagation of monodisperse particle-laden currents triggered by the ...
Esposti Ongaro , Tomaso, Orsucci, Simone, CORNOLTI, FULVIO, Neri, Augusto   +3 more
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