Viscosity Interpolation in Volume of Fluid Method under Single Droplet Impact Condition

In order to accurately model the impact of a fluid droplet onto a solid surface using the volume of fluid method, an accurate method for the interpolation of viscosity is required because the free surface of a fluid changes significantly during droplet impact. There exist several conventional methods for interpolation including the arithmetic and harmonic means of the viscosities, the harmonic mean of the kinematic viscosities, and the blended arithmetic and harmonic means of the viscosities. In this study, a new method is proposed that combines the arithmetic and harmonic means of the kinematic viscosities. To evaluate the accuracy of these methods, the shape of the liquid films resulting from droplet impacts were evaluated through numerical simulation against previous experimental results, finding that the proposed method resulted in the most accurate behavior. The effect of the droplet impact angle on the shape and extent of the resulting liquid film was then examined by numerical simulation under various impact angles using the proposed interpolation method, finding that the horizontal component of the velocity had little effect on the initial spread of the liquid film, but did indeed affect the geometry and extent of spread after a period of time.