Destructiveness of pyroclastic surges controlled by turbulent fluctuations.

ABSTRACT: Pyroclastic surges are lethal hazards from volcanoes that exhibit enormous destructiveness through dynamic pressures of 10⁰-10² kPa inside flows capable of obliterating reinforced buildings. However, to date, there are no measurements inside these currents to quantify the dynamics of this important hazard process. Here we show, through large-scale experiments and the first field measurement of pressure inside pyroclastic surges, that dynamic pressure energy is mostly carried by large-scale coherent turbulent structures and gravity waves. These perpetuate as low-frequency high-pressure pulses downcurrent, form maxima in the flow energy spectra and drive a turbulent energy cascade. The pressure maxima exceed mean values, which are traditionally estimated for hazard asse

SUBMITTER: Brosch E 

PROVIDER: S-EPMC8674289 | biostudies-literature | 2021 Dec

REPOSITORIES: biostudies-literature