The deformation caused by bubble pulsation is larger than that by the shock waves, owing to the large time duration of bubble pulsation. The air may be sucked into the bubble during the hogging process, making the bubble collapse earlier and resulting in a relatively lower sagging deformation for large charge weights of TNT. The steel sheet shows a deformation process of hogging, sagging, and hogging again, due to the actions of shock waves, bubble expansion, bubble collapse, and bubble pulsation. A finite element model was established and benchmarked by comparing the bubble development and deformation distribution from the tests. This study presents underwater explosion tests with three different TNT charge weights to investigate the dynamic responses of a fixed steel sheet. The findings presented in this study provide a reference for bubble-related fields and transient gas–liquid–structure interactions. The influence of the distance parameter γ between the bubble and the plate on the jet pattern and structure load is systematically studied. The physical mechanism affecting the bubble collapse pattern is revealed. The model is verified by comparisons between the experimental and numerical results. In addition, the bubble dynamic behaviors are simulated using the finite volume method, and an FSI model is established based on the overset mesh technology.
The morphological evolution of the bubble and the structural response are recorded using a high-speed camera and strain gauges, respectively. In this study, we conduct experiments examining the interaction between small-charge underwater explosion bubbles and a suspended plate under different initial detonation distances. The effect of fluid–structure interaction (FSI) may increase the damage potential of the structure. Applied to the data already acquired on Mayotte since 2019, this method could allow us to estimate more precisely the volcano effusion rate and its evolution, giving further insights on the feeding system.ĭuring near-field underwater explosions, the structural response induced by the shock wave and bubble load significantly affects the bubble collapse and jet characteristics. By combining both complementary analyses we are able to clearly define the detailed evolution of the lava flows pattern in the short time period of 10 days. Bathymetric information thus provides snapshots of the eruptive area evolution at specific times, when hydro-acoustic signals show its continuous evolution. While bathymetric information gives absolute location of new lava flows, hydro-acoustic events give detailed relative time variations leading to short-term spatial evolution. We compare the time evolution of the hydro-acoustic events locations and bathymetry differences observed between each survey. During the same period, repeated swath bathymetry surveys were performed over an active lava flow field. In October 2020, a line of 10 Ocean Bottom Seismometers was deployed during 10 days, leading to a hand-picked catalog of more than a thousand of hydro-acoustic signals, which have been associated with reactions between hot lava and deep cold ocean waters. In Mayotte, Comoros archipelago, efforts have been made to study and monitor the deep volcanic activity (∼3000 m) currently occurring east of Mayotte through various methods and campaigns on land and at sea. Very different methods can be used and their combination can lead to crucial information about submarine volcanoes behavior. Deep-sea volcanoes are particularly complicated to study due to their remoteness. The majority of Earth volcanism takes place in the deep ocean.
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