Molecular dynamics simulations show that molecular-scale "slip velocity" occurs in the fluid velocity motion near a solid wall, and it is known that its magnitude depends on the wall roughness as well as the physical properties (intermolecular potential) of the solid and fluid. Immersed-boundary flow analysis based on interface approximation using level sets and phase fields is understood to be a continuous approximation of this phenomenon. In this paper, we numerically verify and consider the reproduction of wall boundary conditions using wall roughness and interface approximation models in immersed-boundary flow analysis.
Nobuyuki OSHIMA (2025) studied this question.