ID 343

Dynamic Evaluation of the Finite Particle Method for Computing Surface Tension

 

Abstract:

Under-resolution of the liquid/gas interface is commonplace in contemporary spray simulations. This is problem- atic because surface tension is most important at the smallest scales, and commonly used methods for computing surface tension in Volume of Fluid simulations fail at low resolutions. Failure to properly describe surface tension degrades the fidelity of critical dynamics like capillary breakup, corrupting the resultant droplet size distribution and subsequent dynamics. A newly introduced Finite Particle Method has the capability to characterize the curva- ture and surface tension of low resolution interfaces, but it has not yet undergone dynamic evaluation. This paper presents a dynamic evaluation of the Finite Particle Method through simulations of oscillating ethanol droplets. In low resolution simulations, the Finite Particle Method produces smooth, well-behaved oscillations, whereas the height function method produces erratic oscillations. Performance of the Finite Particle Method is shown to depend on the length scale considered in the calculation of curvature, which is a selectable parameter called the influence radius. Two Finite Particle Method implementations with adaptive influence radii are presented that demonstrate good performance across the range of resolutions relevant to spray simulations. The ability to perform across this range of resolutions makes the Finite Particle Method a valuable new technique for computing interfacial curvature in Volume of Fluid simulations of sprays.