An enhanced instantaneous detonation model for underwater explosions involving condensed explosives.

The dynamic characteristics of underwater explosion phenomena, involving complex multi-phase and multi-interface motions such as shock wave propagation, charge detonation, and bubble motion, are typically predicted using compressible multiphase flow models. However, many existing hydrodynamic solvers neglect the initial explosive detonation process, relying instead on a crude equivalent instantaneous detonation model. This approach fails to accurately capture the dynamic characteristics of near-field underwater explosions. In this study, we present an efficient and high-precision instantaneous detonation model based on a high-order detonation wave dynamics solver. Our model is primarily designed to quantitatively predict the detonation gas product zone state of centrosymmetric charges after initiation at the center of the charge. It can be directly integrated into underwater explosion multiphase solvers without requiring explicit consideration of the explosives' detonation process. By providing a quantitative prediction method, our work facilitates the determination of the initial state of the explosion bubble for various compressible multiphase solvers in this field. This technological breakthrough substantially enhances the precision and dependability of prognosticating underwater explosion dynamics, thereby fostering profound insight into the intricate physical mechanisms governing this complex event.