Numerical Simulations of a Fluidized Granular Flow Entry Into Water: Insights Into Modeling Tsunami Generation by Pyroclastic Density Currents

Battershill, Lily; Whittaker, Colin; Lane, Emily M.; Popinet, Stéphane; White, James D. L.; Power, William; Nomikou, Paraskevi

doi:10.1029/2021jb022855

Cited by 9 publications

(13 citation statements)

References 74 publications

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“…This agrees with the numerical modeling of Battershill et al. (2021), which treats the arriving flow as a continuous Newtonian fluid.…”

Section: Discussionsupporting

confidence: 90%

“…Moreover, particles separating from this monodisperse denser-than-water flow form an upper flow capable of shearing the water surface. This agrees with the numerical modeling of Battershill et al (2021), which treats the arriving flow as a continuous Newtonian fluid. Battershill et al (2021) also highlights the importance of the boundary conditions between the flow and the inclined plane on the wave generation.…”

Section: Flow-water Interactions and Wave Generationsupporting

confidence: 87%

“…This agrees with the numerical modeling of Battershill et al (2021), which treats the arriving flow as a continuous Newtonian fluid. Battershill et al (2021) also highlights the importance of the boundary conditions between the flow and the inclined plane on the wave generation. These boundary conditions control the velocity profile of the flows moving down the inclined plane.…”

Section: Flow-water Interactions and Wave Generationsupporting

confidence: 87%

“…Battershill et al. (2021) also highlights the importance of the boundary conditions between the flow and the inclined plane on the wave generation. These boundary conditions control the velocity profile of the flows moving down the inclined plane.…”

Section: Discussionmentioning

confidence: 99%

“…This separation has typically been attributed to the differences in density within the flow. However, numerical simulations, where the PDC was approximated as a Newtonian fluid, show that even PDCs denser than water are capable of shearing the water surface (Battershill et al., 2021). Subaerial and underwater parts of the flow entrain air and water, respectively, by vertical motion of the flow.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Experimental Modeling of Tsunamis Generated by Pyroclastic Density Currents: The Effects of Particle Size Distribution on Wave Generation

et al. 2022

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Volcanic tsunamis can expand the radius of hazards posed by a volcano well beyond the reach of the eruption itself; however, their source mechanisms are poorly understood. The tsunamigenic potential of pyroclastic density currents was studied experimentally by releasing a fluidized column of glass beads from a reservoir; the beads then ran down an inclined ramp into a water‐filled flume and generated waves. The effects of the particle size distribution on the generated waves were analyzed by comparing the waves generated by flows comprising different proportions of particles of diameters 63–90 μm and 600–850 μm. The flows comprising higher proportions of large particles travel more slowly down the ramp; however, all the flows impact the water at velocities greater than the shallow water wave speed, gh $\sqrt{gh}$, where h is the still‐water depth. The entrance of the fluidized flow into the water generates a solitary‐like leading wave followed by a smaller trough and trailing waves. Upon impact, the flow separates into a part advected with the wave crest and a part which turbulently mixes with water and propagates along the bottom of the flume, forming an underwater gravity current. A higher proportion of large particles makes the flows more porous, allowing the water to penetrate through the flows more easily, slightly decreasing the efficiency of the energy transfer. While this affects the celerity of the waves, the results show that, over the studied range of particle size distributions, all the flows can generate waves of similar amplitudes regardless of the particle size distribution.

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“…This agrees with the numerical modeling of Battershill et al. (2021), which treats the arriving flow as a continuous Newtonian fluid.…”

Section: Discussionsupporting

confidence: 90%

Section: Flow-water Interactions and Wave Generationsupporting

confidence: 87%

Section: Flow-water Interactions and Wave Generationsupporting

confidence: 87%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Experimental Modeling of Tsunamis Generated by Pyroclastic Density Currents: The Effects of Particle Size Distribution on Wave Generation

et al. 2022

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Scenario-based Modelling of Waves Generated by Sublacustrine Explosive Eruptions at Lake Taupō, New Zealand

Hayward

Lane

Whittaker

et al. 2022

Preprint

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Volcanogenic tsunami and wave hazard remains less understood than that of other tsunami sources. Volcanoes can generate waves in a multitude of ways, including subaqueous explosions. Recent events, including a highly explosive eruption at Hunga Tonga-Hunga Ha'apai and subsequent tsunami in January 2022, have reinforced the necessity to explore and quantify volcanic tsunami sources. We utilise a non-hydrostatic multilayer numerical method to simulate 20 scenarios of sublacustrine explosive eruptions under Lake Taupō, New Zealand, across five locations and four eruption sizes. Waves propagate around the entire lake within 15 min, and there is a minimum explosive size required to generate significant waves (positive amplitudes incident on foreshore of > 1 m) from the impulsive displacement of water from the eruption itself. This minimum size corresponds to a mass eruption rate of 5.8 × 10 7 kg s −1 , or VEI 5 equivalent. Inundation is mapped across five built areas and becomes significant near shore when considering only the two largest sizes, above VEI 5, which preferentially impact areas of low-gradient slope. In addition, novel hydrographic output is produced showing the impact of incident waves on the Waikato River inlet draining the lake and is potentially useful for future structural impact analysis. Waves generated from these explosive source types are highly dispersive, resulting in hazard rapidly diminishing with distance from the source. With improved computational efficiency, a probabilistic study could be formulated and other, potentially more significant, volcanic source mechanisms should be investigated.

show abstract

Scenario-based Modelling of Waves Generated by Sublacustrine Explosive Eruptions at Lake Taupō, New Zealand

Hayward

Lane

Whittaker

et al. 2022

Preprint

View full text Add to dashboard Cite

Volcanogenic tsunami and wave hazard remains less understood than that of other tsunami sources. Volcanoes can generate waves in a multitude of ways, including subaqueous explosions. Recent events, including a highly explosive eruption at Hunga Tonga-Hunga Ha'apai and subsequent tsunami in January 2022, have reinforced the necessity to explore and quantify volcanic tsunami sources. We utilise a non-hydrostatic multilayer numerical method to simulate 20 scenarios of sublacustrine explosive eruptions under Lake Taupō, New Zealand, across five locations and four eruption sizes. Waves propagate around the entire lake within 15 minutes, and there is a minimum explosive size required to generate significant waves (positive amplitudes incident on foreshore of >1 m) from the impulsive displacement of water from the eruption itself. This corresponds to a mass eruption rate of 5.8x10ˆ7 kg sˆ-1, or VEI 5 equivalent. Inundation is mapped across five built areas and becomes significant near shore when considering only the two largest sizes, above VEI 5, which preferentially impact areas of low-gradient run-up. In addition, novel hydrographic output is produced showing the impact of incident waves on the Waikato river inlet draining the lake, and is potentially useful for future structural impact analysis. Waves generated from these explosive source types are highly dispersive, resulting in hazard rapidly diminishing with distance from the source. With improved computational efficiency, a probabilistic study could be formulated and other, potentially more significant, volcanic source mechanisms should be investigated.

show abstract

Numerical Simulations of a Fluidized Granular Flow Entry Into Water: Insights Into Modeling Tsunami Generation by Pyroclastic Density Currents

Cited by 9 publications

References 74 publications

Experimental Modeling of Tsunamis Generated by Pyroclastic Density Currents: The Effects of Particle Size Distribution on Wave Generation

Experimental Modeling of Tsunamis Generated by Pyroclastic Density Currents: The Effects of Particle Size Distribution on Wave Generation

Scenario-based Modelling of Waves Generated by Sublacustrine Explosive Eruptions at Lake Taupō, New Zealand

Scenario-based Modelling of Waves Generated by Sublacustrine Explosive Eruptions at Lake Taupō, New Zealand

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