Liangtao Liu

• Doctor of Engineering
• Associate Professor at Nanjing University of Science and Technology

The dynamics of a toroidal bubble near a solid wall for a large part of stand-off parameters γ (γ=d/Rmax, d is the distance between the solid wall and the bubble centre at the moment of formation and Rmax is the maximum bubble radius) have been extensively studied, but some mechanics of a toroidal bubble are not completely clear, especially for the...

The bubble dynamics in a viscous liquid have significant applications, but the influence of viscosity on bubble dynamics near a solid wall are still not fully understood, especially for the toroidal bubble. In this paper, a numerical method is presented to study toroidal bubble dynamics near a solid wall in the viscous liquid. The liquid phase is a...

The pulsation bubble dynamics near a free surface have significant engineering applications. Based on the finite volume method, a front tracking method coupled with an extrapolation technique is applied to study the transient characteristics of the pulsation bubble near the free surface with the different stand-off distance parameter γ and buoyancy...

Bubble has significant applications in ocean engineering. Aiming at the difficulty of conducting the underwater explosion bubble experiment with large charge in deep water, this paper adopts a new way to deal with this problem. On the basis of similarity theory, it is found that by considering the scaling relationship of gravitational acceleration,...

The interactions between bubbles and water waves have important applications in ocean engineering, and their coupling characteristics are strongly associated with the wave phase angle, wavelength, and wave amplitude. Based on the assumption that the liquid is inviscid and incompressible, the coupling characteristics between bubbles and water waves...

This study investigates the deformation characteristics of a ring-stiffened cylindrical shell induced by shock waves and coalesced bubbles in double-charge underwater explosions. A numerical model for coupling underwater multi-point explosion loads with the cylindrical shell is established by the Arbitrary Lagrange Euler method, and underwater expl...

Interactions between multiple bubbles near a structure are applicable in several fields such as military or industrial engineering. In this paper, interactions between two underwater explosion bubbles near a floating structure are investigated. Experiments were carried out in a cubic explosion tank, with high-speed images to record the expansion, c...

In order to provide a theoretical basis for studying the shock wave propagation and evolution generated by cylindrical charge of near-field underwater explosion, the characteristics of initial shock waves generated by cylindrical charge are studied. First, a new theoretical model for initial shock waves is proposed by the polar curve method. Based...

In order to analyze the influence of a water medium on the forming process and penetration performance of a shaped charge jet, a comparative study was carried out on an underwater shaped charge jet (USCJ) and a shaped charge jet (SCJ) in air. The virtual mass hypothesis is proposed to analyze the forming mechanism of USCJs. The arbitrary Lagrangian...

In order to study the directional enhancement effect of underwater explosion for cylindrical explosive with large length-to-diameter ratio, based on the experiment and ALE method, the influences of length-to-diameter ratio on the shock wave and bubble load as well as the structural response of nearby water-back copper plate are analysed. Meanwhile,...

The water jet produced by underwater explosion bubbles during the contraction stage can produce a strong impact on the nearby structure, and its impact characteristics are significantly associated with the explosion distance and azimuth angle. Experiment and ALE method are used to investigate its impact characteristics on the plate structure at dif...

This study aims to investigate the formation characteristics and penetration performance of an underwater conical shaped charge jet. First, a new theoretical model for underwater jet formation is proposed by the virtual mass method. Based on the theoretical model and the ALE algorithm, the influences of standoff height, cone angle, liner thickness...

An underwater multipoint synchronous explosion can enhance the damage effect of an underwater explosion shock wave on a structure. This study investigates the damage effect of an underwater multipoint synchronous explosion on an air-backed clamped circular plate. First, we derive the theoretical formula for the superposition of underwater explosion...

The bubble motion in the shallow water environment has significant applications in underwater explosion and seabed exploration, where the bubble characteristics are mainly associated with the two types of stand-off distance parameters γf and γs (the parameters are defined in Section 2.3). Based on the assumption that the liquid is inviscid and inco...

A calculation method for the shock dynamic bending moment on a ship subjected to underwater explosion was studied. Based on the discrete time transfer matrix method combined with the non-homogeneous precise integration method, the hull beam was equivalent to a variable cross-section beam，and the precise time transfer matrix (PTTM) of shock dynamic...

A simplified open floating slender structure is used to investigate the dynamic behaviors of the warship in this paper. The deformation and damage mechanisms of the simplified open floating slender structure subjected to the underwater explosion are studied using the experiment and the Coupled Eulerian-Lagrangian (CEL) method. Firstly, a validation...

Based on the algorithm of Coupled Eulerian Lagrangian (CEL), the processes of a shaped charge jet formation after the shaped charge explosion and its penetration into the warship broadside protective structure were simulated by AUTODYN. The numerical results were compared with the experimental results to validate the numerical method. The influence...

In this paper, a coupling eulerian langarian method (CEL) is used to study the interaction between a collapsing underwater explosion bubble and a steel plate. The VOF method is used to simulate the physical process of bubble growth, contraction and collapse, while the finite element method is used to calculate dynamic response of the steel plate. B...

The wall pressure caused by underwater explosion is always a key problem in the anti-explosion design of naval ships. Notably, the accurate wall pressure caused by underwater explosion bubble is one of the most difficult parts due to the significant nonlinear deformation of the bubble. In present study, the dynamics of an underwater explosion bubbl...

Cavitation effects play a substantial role in the dynamic response of marine structures. In the previous numerical studies, it's assumed that the incident explosive loading is reflected by the horizontal free surface. But the cavitation phenomenon near the water wave has rarely been investigated. In this paper, we propose a novel 2D underwater expl...

The deformation mechanism of warships subjected to underwater explosion is very important to the survivability assessment of warships. Therefore, in this study the deformation mechanism of a hull girder similar to a real warship structure subjected to underwater explosion loads has been investigated experimentally and numerically. In addition, the...

Bubbles are becoming a threat to the measurement of equipment and human activities in the moonpool, while little is known about the characteristics of bubbles in the moonpool. We aim to investigate the motion patterns and characteristic of bubbles in the moonpool. To support the investigation, experiments were conducted in a water tunnel. Images of...

The purpose of this study was to investigate the whipping response of a cylinder subjected to underwater explosion. A semi-analytical method contains shock wave and bubble pulsation load was established. Empirical formula of shock wave and G&H model was used to simulate the underwater explosion loading while hydrodynamic force was predicted by Tayl...

The oscillation of a bubble near the free surface confined by a cylindrical tank is simulated by the axisymmetric boundary integral method (BIM) code. Firstly, the axis-symmetrical numerical modeling is established based on the incompressible potential flow theory, which is followed by the validation with mechanism experiments carried out using the...