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A Lab-Scale Experiment to Measure Terminal Velocity of Volcanic Ash
Author(s)
Language
English
Obiettivo Specifico
3.6. Fisica del vulcanismo
Status
Published
JCR Journal
JCR Journal
Title of the book
Issue/vol(year)
4/60 (2011)
Pages (printed)
1340 - 1347
Issued date
April 1, 2011
Keywords
Abstract
In this paper, a novel methodology to measure trajectory
and terminal velocity of volcanic ash in laboratory is
presented. The methodology consists of the following: 1) planning
a lab-scale experiment in order to reproduce the sedimentation
processes of fine volcanic ash based on the principle of dynamic
similarity; 2) realizing the experimental setup using a glass tank
filled with glycerine, a webcam-based vision system and a dedicated
image postprocessing tool able to estimate the position
and the terminal velocity of any particle falling in the tank;
3) performing a calibration procedure to accurately estimate the
uncertainty on particle velocity; and 4) comparing the experimental
results with estimations obtained by some particle fallout
models available in literature. Our results show that there is a good
agreement between experimental terminal velocities and those
obtained applying a model which includes information on particle
shape. The proposed methodology allows us to investigate how the
particle shape affects the sedimentation processes. Since the latter
is strategic to improve the accuracy on modeling ash fallout, this
work will contribute to reduce risks to aviations during explosive
eruptions.
and terminal velocity of volcanic ash in laboratory is
presented. The methodology consists of the following: 1) planning
a lab-scale experiment in order to reproduce the sedimentation
processes of fine volcanic ash based on the principle of dynamic
similarity; 2) realizing the experimental setup using a glass tank
filled with glycerine, a webcam-based vision system and a dedicated
image postprocessing tool able to estimate the position
and the terminal velocity of any particle falling in the tank;
3) performing a calibration procedure to accurately estimate the
uncertainty on particle velocity; and 4) comparing the experimental
results with estimations obtained by some particle fallout
models available in literature. Our results show that there is a good
agreement between experimental terminal velocities and those
obtained applying a model which includes information on particle
shape. The proposed methodology allows us to investigate how the
particle shape affects the sedimentation processes. Since the latter
is strategic to improve the accuracy on modeling ash fallout, this
work will contribute to reduce risks to aviations during explosive
eruptions.
Type
article
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AshTerminalVelocity.pdf
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