The paper provides a brief introduction to the near-wall problem of LES and how it can be solved through modeling of the near-wall turbulence. The distinctions and key differences between different approaches are emphasized, both in terms of fidelity (LES, wall-modeled LES, and DES) and in terms of different wall-modeled LES approaches (hybrid LES/RANS and wall-stress-models). The focus is on approaches that model the wall-stress directly, i.e., methods for which the LES equations are formally solved all the way down to the wall. Progress over the last decade is reviewed, and the most important and promising directions for future research are discussed.

In this review, the analysis of melting and solidification phenomena and the mechanism of the occurrence of defects as well as the analysis of melting and solidification using the numerical simulation in laser powder bed fusion (LPBF) process were introduced. In addition, the strategies of suppression of defects were described. The melting and solidification phenomena during LPBF process are relatively similar to those during welding. Since the plume brings about the strong recoil pressure on the melt pool, the keyhole takes place. And when the depth of keyhole becomes more than a threshold, the keyhole pore remains at the bottom of melt pool. Since the plume also brings about spattering and blows out powder, the gas pores are prone to occur easily. The micro-simulation of melting and solidification enables to reproduce the real phenomena. The macro-simulation of melting and solidification phenomena is one of the effective tools to predict the optimum fabrication condition. In order to prevent the occurrence of defects, it is significant not only to obtain the optimum fabrication condition using the process map but also to develop the simulation software. In addition, the use of the monitoring and feedback control system is greatly effective. Therefore the development of the cyber-physical system is needed.

Deformability of epithelial tissues plays a crucial role in embryogenesis, homeostasis, wound healing, and disease. The deformability is determined by the mechanical balance between active force generation and passive response of cells. However, little is known about how multiple cells in epithelial tissues passively respond to external forces. Using a 3D vertex model, we performed computational simulations of longitudinal tension and compression tests of an epithelial tube. Under tension, the tube extended with necking as exhibiting cell rearrangements that play a role in reducing local stiffness of the tube. On the other hand, under compression, the tube buckled with kinking without cell rearrangements. The cell rearrangements occurred when apical and basal cell surfaces stored elastic deformation energies. These results illustrate the variance of deformation modes of epithelial tissues in the single cell level as well as the importance of cell rearrangements in regulating epithelial deformability.