A Boundary Coefficient Reconstruction Strategy Based on Contact Angle for SPH

The size of the contact angle is a key coefficient to characterize the surface properties. The ambiguity of the contact angle properties in the SPH simulation will affect the simulation of the droplet on the interface, especially on the complex hydrophilic-hydrophobic interface. In order to solve this problem, the previous particle methods either used the method of controlling the surface tension coefficient or the method of presetting the virtual contact angle to adjust the surface tension of the droplet, thereby adjusting the contact angle between the droplet and the interface. However, although these methods reflect the characteristics of the fluid, they do not characterize the characteristics of the interface, resulting in the simulated interface characteristics often being of a single nature and insufficient accuracy. In this paper, we added an interface-adaptive adhesion coefficient to characterize the interface characteristics, and proposed a feedback algorithm to determine the size of the adhesion coefficient, and use this coefficient to characterize the hydrophilic-hydrophobic properties of the droplet on the interface. Based on this coefficient, we can accurately characterize the hydrophilicity and hydrophobicity of different interfaces, and successfully simulate the process of droplet movement on complex surfaces with different contact angle characteristics.