Strong interaction between an oscillating bubble and elastic steel plates in underwater contact explosions

The fluid–structure interaction between elastic plates of varying thicknesses (4–20 mm) and underwater explosion bubbles was numerically studied via the finite element method. An underwater explosion experiment near a steel plate was carried out to verify the numerical approach. In addition to rigid body motion, it was observed that the substantial deformation of thin plates markedly impacts bubble collapse and jet formation. Specially, the deformation degree of the plate critically determines whether bubble pinching occurs. Such bubble pinching results in high-speed, needle-like jets, with their impact velocity rising as the vertical position of the annular necking region increases. This position is mainly dictated by plate motion and does not correlate monotonically with structural thickness. Once the plate thickness surpasses a critical threshold, the necking position gradually ascends until it vanishes.