FPLUME-1.0: An integral volcanic plume model accounting for ash aggregation

Abstract

Abstract. Eruption source parameters (ESP) characterizing volcanic eruption plumes are crucial inputs for atmospheric tephra dispersal models, used for hazard assessment and risk mitigation. We present FPLUME-1.0, a steady-state 1-D (one-dimensional) cross-section-averaged eruption column model based on the buoyant plume theory (BPT). The model accounts for plume bending by wind, entrainment of ambient moisture, effects of water phase changes, particle fallout and re-entrainment, a new parameterization for the air entrainment coefficients and a model for wet aggregation of ash particles in the presence of liquid water or ice. In the occurrence of wet aggregation, the model predicts an effective grain size distribution depleted in fines with respect to that erupted at the vent. Given a wind profile, the model can be used to determine the column height from the eruption mass flow rate or vice versa. The ultimate goal is to improve ash cloud dispersal forecasts by better constraining the ESP (column height, eruption rate and vertical distribution of mass) and the effective particle grain size distribution resulting from eventual wet aggregation within the plume. As test cases we apply the model to the eruptive phase-B of the 4 April 1982 El Chichón volcano eruption (México) and the 6 May 2010 Eyjafjallajökull eruption phase (Iceland). The modular structure of the code facilitates the implementation in the future code versions of more quantitative ash aggregation parameterization as further observations and experiment data will be available for better constraining ash aggregation processes.

Uncertainties in volcanic plume modeling: A parametric study using FPLUME

“…This section summarizes the governing equations and parameterization of the FPLUME model (for a more detailed description see Folch et al, 2016. FPLUME is a 1D steady-state volcanic plume model based on the Buoyant Plume Theory of Morton et al (1956)) that accounts for different options for estimating air entrainment (Carazzo et al, 2006(Carazzo et al, , 2008bTate and Middleton, 2000), plume bending due to wind effects (Bursik, 2001), fallout of particles from the plume (Bursik, 2001), particle re-entrainment (Ernst et al, 1996), water phase changes (Woods, 1988;Woods, 1993), particle wet aggregation (Costa et al, 2010;Brown et al, 2012), and column collapse.…”

A New One‐Equation Model of Fluid Drag for Irregularly Shaped Particles Valid Over a Wide Range of Reynolds Number

“…In volcanology and Earth sciences in general, the shape-dependent aerodynamic drag is crucial in controlling the transport and deposition of nonspherical solid particles in dust storms (e.g., Doronzo et al, 2015;Kok et al, 2012), rivers and lakes (e.g., DIOGUARDI ET AL. AERODYNAMIC DRAG OF IRREGULAR PARTICLES 144 Zhu et al, 2017), pyroclastic flows (e.g., Dellino et al, 2008;, eruptive columns (e.g., Cerminara et al, 2016;Folch et al, 2016), and distal ash clouds (e.g., Beckett et al, 2015;Bonadonna et al, 2012;Bonasia et al, 2010;Costa et al, 2012Costa et al, , 2006). Therefore, a major effort has been posed to find reliable shapedependent drag laws that work on the widest possible range of fluid dynamic regimes quantified by Re (Alfano et al, 2011;Bagheri & Bonadonna, 2016;Chhabra et al, 1999;Chien, 1994;Dellino et al, 2005;Dioguardi et al, 2017;Dioguardi & Mele, 2015;Ganser, 1993;Haider & Levenspiel, 1989;Hölzer & Sommerfeld, 2008;Loth, 2008;Pfeiffer et al, 2005;Swamee & Ojha, 1991;Tran-Cong et al, 2004;Wilson & Huang, 1979).…”

Plume-SPH 1.0: A three-dimensional, dusty-gas volcanic plume model based on smoothed particle hydrodynamics

“…Several 1D (one dimensional) volcanic plume models have been developed in the past few decades, ranging from the most basic 1D model (Woods, 1988) which only accounts for mass conservation to more recently developed 1D models (Bursik,20 2001; Mastin, 2007;Degruyter and Bonadonna, 2012;Woodhouse et al, 2013;Devenish, 2013;de'Michieli Vitturi et al, 2015;Folch et al, 2016;Pouget et al, 2016) which tend to account for more comprehensive physics effects. For example, FPLUME-1.0 (Folch et al, 2016) accounts for wind effect, entrainment of moisture, water phase change, particle fallout and re-entrainment and even wet aggregation of ash.…”

“…For example, FPLUME-1.0 (Folch et al, 2016) accounts for wind effect, entrainment of moisture, water phase change, particle fallout and re-entrainment and even wet aggregation of ash. However, in these 1D models, the entrainment of air is evaluated based on two coefficients: entrainment coefficient for the vertical plume and the entrainment coefficient that describes the effect of 25 wind.…”

“…To summarize, our model is not valid for eruptions where wind effect plays a significant role in its development, usually refered as a weak plume. Our model also lacks the ability in modeling plumes with large particles or eruptions in which microphysics plays non-ignorable roles, such as a eruption of El Chichón volcano on 20 April 4th 1982 (Sigurdsson et al, 1984;Folch et al, 2016). We are focussed here on developing the SPH based methodoloy in the context of the more basic (and more critical) aspects of volcanic plume and therefore devote our effort to this relative simpler model.…”