Project

Back to overview

Experimental and field investigations of particle aggregation

English title Experimental and field investigations of particle aggregation
Applicant Bonadonna Costanza
Number 144470
Funding scheme Project funding
Research institution Département des sciences de la Terre Université de Genève
Institution of higher education University of Geneva - GE
Main discipline Mineralogy
Start/End 01.11.2012 - 31.08.2014
Approved amount 129'020.00
Show all

All Disciplines (2)

Discipline
Mineralogy
Other disciplines of Earth Sciences

Keywords (4)

explosive volcanism; tephra ; laboratory experiments; particle aggregation

Lay Summary (English)

Lead
Lay summary

This 2-year proposal is the continuation of the currently FNS funded project (No: 200020_125024), which supported the first two years of the PhD project of Mr Gholamhossein Bagheri at the Unit of Geological Risk of the University of Geneva, focused on the study of particle settling velocity and aggregation. The first two years were dedicated to the completion of a vertical wind tunnel (in collaboration with the Ecole d'ingénieurs de Genève (CMEFE - Groupe de compétences en mécanique des fluides et procédés énergétiques / IMEC) (http://www.unige.ch/sciences/terre/mineral/volcano/lab.html#dynamics), to the development of a dedicated Particle Tracking Velocimetry (PTV) software and to the experiments on particle settling velocity. With this new 2-year proposal we plan to fund the remaining two years of Mr G. Bagheri’s PhD with the main objectives of carrying out both field and experimental investigations of particle aggregation crucial to the development of a solid parameterization of particle aggregation.

Processes of particle aggregation play a fundamental role in the sedimentation of tephra from volcanic plumes and, in particular, in the sedimentation of the fine-ash fraction (<63 microns). In fact, field observations and laboratory experiments have shown that particles with diameter <100 microns do not fall individually but they aggregate in clusters of different types, mainly depending on particle and atmospheric properties. Unfortunately, even though both analytical and numerical models typically used to describe tephra transport and sedimentation have now reached a high level of sophistication, an accurate and versatile model of particle aggregation does not exist. This has important implications on the associated long-term hazard assessments of tephra sedimentation, real-time forecast of ash-rich plumes and health-hazard assessments (e.g., 2010 Eyjafjallajökull, Iceland, and 2011 Puyehue-Cordon Caulle, Chile eruptions).

We propose to combine experimental and field investigations of particle aggregation for the development of an accurate parameterization of particle aggregation. Real volcanic particles will be used in order to validate lab experiments with field observations. We are also planning to carry out field observations of particle aggregation during the current eruption of Soufrière Hills Volcano, Montserrat (WI), characterized by ash-rich fallout. We will measure settling velocity of particle clusters in situ and we will collect individual clusters for analysis in the lab.

Objectives of this proposal are in line with the main objectives of both the International Volcanic Ash Task Force and the IAVCEI Commission on tephra hazard modelling, as highlighted during the first IAVCEI-WMO Ash Dispersal Forecast and Civil Aviation workshop (Geneva 18-20 October 2010) (http://www.unige.ch/sciences/terre/mineral/CERG/Workshop.html). This guarantees the high scientific level of the project and the active role of the Unit of Geological Risk of the University of Geneva within the international Community. Dissemination of the project outcomes will also be facilitated by the MeMoVolc and NEMOH European networks for which Prof. C. Bonadonna is in the Steering Committee.

Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants

Employees

Publications

Publication
Aerodynamics of Volcanic Particles: Characterization of Size, Shape, and Settling Velocity
Bagheri Gholamhossein, Bonadonna Costanza (2016), Aerodynamics of Volcanic Particles: Characterization of Size, Shape, and Settling Velocity, in Shona Mackie Katharine Cashman Hugo Ricketts Alison Rust Matt Watson (ed.), Elsevier, Amsterdam, Oxford, Cambridge, 39-52.
On the drag of freely falling non-spherical particles
Bagheri Gholamhossein, Bonadonna Costanza (2016), On the drag of freely falling non-spherical particles, in Powder Technology, 301, 526-544.
Timing and nature of volcanic particle clusters based on field and numerical investigations
Bagheri Gholamhossein, Rossi Eduardo, Biass Sébastien, Bonadonna Costanza (2016), Timing and nature of volcanic particle clusters based on field and numerical investigations, in Journal of Volcanology and Geothermal Research, 1.
Dedicated vertical wind tunnel for the study of sedimentation of non-spherical particles
Bagheri Gholamhossein H., Bonadonna Costanza, Manzella Irene, Pontelandolfo Piero, Haas Patrick E. (2013), Dedicated vertical wind tunnel for the study of sedimentation of non-spherical particles, in Review of Scientific Instruments, 84(5), 84.
On the characterization of size and shape of irregular particles
Bagheri GH, Bonadonna C, Manzella I, Vonlanthen P, On the characterization of size and shape of irregular particles, in Powder Technology.

Collaboration

Group / person Country
Types of collaboration
Patrick Haas (Ecole d'ingénieurs de Genève - CMEFE - IMEC) Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
Jean-Luc Falcone (CUI, Departement d'Informatique, University of Geneva) Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Research Infrastructure
Adam Durant (Norwegian Institute for Air Research) Norway (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Research Infrastructure

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
VERTIGO 1st Workshop Individual talk Particle sedimentation from volcanic plumes 27.09.2014 Stromboli, Italy Bonadonna Costanza;
International Conference on Atmospheric Dust Talk given at a conference New Strategies For The Characterization Of Size, Shape And Terminal Velocity Of Irregular Particles 01.06.2014 Castellaneta Marina, Italy Bagheri Gholamohossein;
European Geophysical Union Conference Talk given at a conference New Strategies For The Characterization Of Size, Shape And Terminal Velocity Of Irregular Particles 27.04.2014 Vienna, Austria Bagheri Gholamohossein;
IAVCEI (International Association of Volcanology and Chemistry of the Earth's Interior) Conference Talk given at a conference A new model for the predication of drag of non-spherical volcanic particles 20.07.2013 Kagoshima, Japan Bagheri Gholamohossein;


Self-organised

Title Date Place
Wind tunnel workshop 26.03.2014 University of Geneva, Switzerland

Associated projects

Number Title Start Funding scheme
156255 Experimental and field investigations of particle aggregation 01.06.2015 Project funding
125024 Numerical, experimental and field investigations of particle aggregation 01.08.2009 Project funding
125024 Numerical, experimental and field investigations of particle aggregation 01.08.2009 Project funding

Abstract

This 2-year proposal is the continuation of the currently FNS funded project (No: 200020_125024), which is supporting the first two years of the PhD project of Mr Gholamhossein Bagheri at the Unit of Geological Risk of the University of Geneva, focused on the study of particle settling velocity and aggregation. The first two years were dedicated to the completion of a vertical wind tunnel (in collaboration with the Ecole d'ingénieurs de Genève (CMEFE - Groupe de compétences en mécanique des fluides et procédés énergétiques / IMEC), to the development of a dedicated Particle Tracking Velocimetry (PTV) software and to the experiments on particle settling velocity. With this new 2-year proposal we plan to fund the remaining two years of Mr G. Bagheri’s PhD with the main objectives of carrying out both field and experimental investigations of particle aggregation crucial to the development of a solid parameterization of particle aggregation based on the theory of Smoluchowski (1916). Processes of particle aggregation play a fundamental role in the sedimentation of tephra from volcanic plumes and, in particular, in the sedimentation of the fine-ash fraction (<63 microns). In fact, field observations and laboratory experiments have shown that particles with diameter <100 microns do not fall individually but they aggregate in clusters of different types, mainly depending on particle and atmospheric properties. Unfortunately, even though both analytical and numerical models typically used to describe tephra transport and sedimentation have now reached a high level of sophistication, an accurate and versatile model of particle aggregation does not exist. This has important implications on the associated long-term hazard assessments of tephra sedimentation, real-time forecast of ash-rich plumes and health-hazard assessments (e.g., 2010 Eyjafjallajökull, Iceland, and 2011 Puyehue-Cordon Caulle, Chile eruptions). Previous experimental investigations have resulted in empirical parameterizations of particle aggregation in both wet and dry environment, but, that cannot be generalized to provide a comprehensive aggregation model. Numerical studies have also provided important insights (mainly on wet aggregation), but, due to the complex nature of these highly sophisticated models, they still require validation with field observations and they cannot be easily applied to hazard assessments of any form. We propose to combine experimental and field investigations of particle aggregation for the development of an accurate parameterization of particle aggregation based on the theory of Smoluchowski (1916). In particular, we are planning to run experiments for particle collision and for both dry and wet aggregation using our dedicated vertical wind tunnel. We are particularly interested in investigating aggregation processes over time in order to understand what controls the growth rate of particle clusters. Real volcanic particles will be used in order to validate lab experiments with field observations. We are also planning to investigate collision and sticking efficiency separately and to study the relative effect of differential settling velocity and turbulence on particle collision. In addition, we are also planning to carry out field observations of particle aggregation during the current eruption of Soufrière Hills Volcano, Montserrat (WI), characterized by ash-rich fallout. We will measure settling velocity of particle clusters in situ and we will collect individual clusters for analysis in the lab (i.e. grainsize, porosity, componentry, particle properties, SEM analyses).The project team is particularly well-qualified because it includes experts in the study of tephra deposits (Prof. C Bonadonna), aerodynamics sciences (Prof. P Haas), multi-scale modeling (Dr. JL Falcone) and both experimental and field characterization of particle aggregation (Dr M James and Dr A Durant). The PhD candidate (Mr G. Bagheri) is also ideal for this project as he has already proved his scientific dedication and has already produced significant contributions in the field of numerical and experimental fluid dynamics. He will be helped by a Master student (Ms Fiona Burns) during field work on Montserrat. Objectives of this proposal are in line with the main objectives of both the International Volcanic Ash Task Force and the IAVCEI Commission on tephra hazard modelling, as highlighted during the first IAVCEI-WMO Ash Dispersal Forecast and Civil Aviation workshop (Geneva 18-20 October 2010). This guarantees the high scientific level of the project and the active role of the Unit of Geological Risk of the University of Geneva within the international Community. We are planning to publish our results in high-impact-factor journals (e.g., JGR, Geology and Powder Technology), to present our work to the international scientific Community (i.e. EGU and IAVCEI conferences) and to directly interact with operational agencies involved in real-time forecasting of volcanic clouds during volcanic crisis (i.e., Volcanic Ash Advisory Centers). Dissemination of the project outcomes will also be facilitated by the MeMoVolc and NEMOH European networks for which Prof. C. Bonadonna is in the Steering Committee.
-