Publication Date:
2017-04-04
Description:
We present the results of laboratory experiments on the aggregation and disaggregation of colliding volcanic ash particles. Ash particles of different composition and size 〈90 µm were held in turbulent suspension and filmed in high speed while colliding, aggregating, and disaggregating, forming a growing layer of electrostatically bound particles along a vertical plate. At room conditions and regardless of composition, 60–80% of the colliding particles smaller than 32 µm remained aggregated. In contrast, aggregation of particles larger than 63 µm was negligible, and, when a layer formed, periods when disaggregation (mainly by collisions or drag) exceeded aggregation occurred twice as frequently than for smaller particles. An empirical relationship linking the aggregation index, i.e., the effective fraction of aggregated particles surviving disaggregation, to the mean particle collision kinetic energy is provided. Our results have potential implications on the dynamics of volcanic plumes and ash mobility in the environment.
Description:
INGV-DPC project V1 “Probabilistic evaluation of volcanic hazard”; EU Seventh Programme FP7 “MED-SUV” grant agreement 308665
Description:
Published
Description:
1068–1075
Description:
3V. Dinamiche e scenari eruttivi
Description:
2IT. Laboratori sperimentali e analitici
Description:
JCR Journal
Description:
restricted
Keywords:
volcanic ash
;
disaggregation
;
experimental modeling
;
volcanic plumes
;
aggregation processes
;
colliding particles
;
sticking rate
;
01. Atmosphere::01.01. Atmosphere::01.01.07. Volcanic effects
;
04. Solid Earth::04.08. Volcanology::04.08.02. Experimental volcanism
;
04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
;
05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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