A new model for calculation of surface tension force in PLIC-VOF methods

Conventional methods for modeling of surface tension force in PLIC-VOF methods, such as CSF, Continuum Surface Stress CSS and also Meier's method, convert the surface tension force into a body force. Not only do they include the force in the interfacial cells but also in the neighboring cells. Therefore, they produce spurious currents. In addition, the pressure jump, due to the surface tension, is not calculated accurately in these methods. In this paper a more accurate method for the application of interface force in the computational modeling of free surfaces and interfaces which use PLIC-VOF methods is developed. This method is based on the evaluation of the surface tension force only in the interfacial cells and not the neighboring cells. Also the normal and the interface surface area needed for the calculation of the surface tension force is calculated more accurately. The present method is applied to a 2-D motionless bubble of gas and an oscillating initially oval shape drop. Similar problems are also simulated using Meier's model of surface tension force, CSS model and CSF model with and without the density correction factor. It is shown that the present model produces better results in calculating the pressure jump across the interface as well as the shape of the drop or bubbles. (author)