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Physically-Based Simulation
Fluid Interaction
Ice and Snow
Shell Deformation
User Behavior Analysis
Sentiment Analysis
Outlier Detection
Automatic Player Behavior Analysis
Adaptive Agent Navigation
Crowd Simulation
Graphics Applications
Artificial Life
3D Geometry Processing
Real domain data visualization
Integral MLS Surface Model
SDF-based Geometry Synthesis
Point-based Geometry and Modeling
Texture Processing
High Order Surface Tracking

1. Abstract

At interfaces between different fluids, properties such as density, viscosity, and molecular cohesion are discontinuous. To animate small-scale details of incompressible viscous multi-phase fluids realistically, we focus on the discontinuities in the state variables that express these properties. Surface tension of both free and bubble surfaces is modeled using the jump condition in the pressure field; and discontinuities in the velocity gradient field, driven by viscosity differences, were also considered. To obtain derivatives of the pressure and velocity fields with sub-grid accuracy, they are extrapolated across interfaces using continuous variables based on physical properties. The numerical methods that we present are easy to implement and do not impact the performance of existing solvers. Small-scale fluid motions, such as capillary instability, breakup of liquid sheets, and bubbly water can all be successfully animated.

2. Discontinuous Fluid

There is a discontinuous pressure profile at the interface Γ between two different fluids. The figure shows the discontinuous pressure at the interface, Γ. The pressure of the right and left sides are different across Γ. This makes it difficult to differentiate the pressure across Γ using standard finite differencing.

3. Anisotropic Particle Level set

This paper presents how to track the surface of a multiphase fluid more accurately by using the particle level set method with anisotropic instead of spherical particles. While we use the weighted version of principal component analysis (WPCA) to construct the anisotropic particles, its computational cost is high. We adopt the distribution of particles from the directional derivative to generate the anisotropic particles. Compared to particle level set method, our approach provides more details of surface, corrects numerical dissipation, and preserves the volume of the fluid. Furthermore, we present particle-based fluid simulations with surface reconstruction that uses anisotropic particles.

4. Related Publications

[1] "Discontinuous Fluids," Jeong-Mo Hong and Chang-Hun Kim, ACM Transactions on Graphics (In Proceedings of ACM SIGGRAPH 2005), Volume 24, Number 3, pp. 915-920, 2005.

[2] "Anisotropic Particle Level-Set Method for Multiphase Fluid," Po-Ram Kim, Ho-Young Lee, Jung Lee and Chang-Hun Kim, Journal of Research and Practice in Information Technology, to appear, 2012.