Ulsan National Institute of Science and Technology · Engineering
Professor Hyungson Ki's research lab specializes in numerical modeling and simulation of laser-material interactions, with a focus on multiphase flows, phase transformations, and energy transfer dynamics in high-precision manufacturing processes such as laser drilling, welding, and micromachining. The lab develops advanced computational frameworks combining the level set method, ray tracing, and finite-difference time-domain (FDTD) techniques to model complex phenomena including self-evolving cavities, thermocapillary convection, recoil pressure, and ultrafast laser interactions. Their work spans from femtosecond laser ablation in semiconductors to high-energy-density processes involving phase change and plasma formation, emphasizing accurate prediction of transient thermal and fluid dynamics. The lab’s research bridges fundamental physics with industrial applications in materials processing and additive manufacturing.
Figures are computed from collected data and may differ slightly.
A high-energy-density laser beam-material interaction process has been simulated considering a self-evolving liquid-vapour interface profile. A mathematical scheme called the level-set technique has been adopted to capture the transient liquid-vapour interface. Inherent to this technique are: the ability to simulate merger and splitting of the liquid-vapour interface and the simultaneous updating of the surface normal and the curvature. Unsteady heat transfer and fluid flow phenomena are modelle
In laser drilling and keyhole welding, multiple reflection phenomena determine how the energy is transferred from the laser beam to the workpiece, and, most importantly, all other physics such as fluid flow, heat transfer, and the cavity shape itself depend on these phenomena. In this study, a multiple reflection model inside a self-consistent (or self-evolving) cavity has been developed based on the level set method and ray tracing technique. In the case of drilling, it is observed that the las
ABSTRACT A numerical method for multiphase incompressible thermal flows with solid–liquid and liquid–vapor phase transformations is presented. The flow is mainly driven by thermocapillary force and vaporization. Based on the level set method and mixture continuum model, a set of governing equations valid for solid, liquid, and vapor phases is derived, considering phase boundary conditions as source terms in the transport equations. The vaporization process is treated as a source term in the cont
Open papers in the app to read, cite, and organize with AI.
