This Thesis introduces effective methods to simulate small-scale features in thin liquid jets and muddy water animation. In the microscopic scope, these fluids show interesting phenomena that make the simulation more realistic. The existing fluid simulation methods that represent small-scale features require extremely high resolution. However, since the features are found in a microscopic area, the high resolution reduces the efficiency of the total simulation. Therefore, this paper proposes novel simulation models for thin liquid jets and muddy water animation.
First of all, this thesis proposes a novel approach to represent thin liquid jets. In a thin liquid jet from faucet, shower, fountain, etc., the initially smooth jet surface is gradually perturbed with time to eventually produce droplets. This thesis proposes to model such a liquid jet with a thread. It is defined as a series of nodes, and an edge connecting a pair of nodes is filled with volume particles. The jet's large-scale behavior is simulated by moving a relatively small number of nodes whereas the small-scale detail is described using the volume particles. The proposed method is capable of handling a large number of jets and describing the special effects, such as liquid chain and fishbone, produced by impinging jets. Furthermore, the proposed method can be neatly integrated into existing fluid simulation systems at a small cost.
Secondly, this thesis proposes simulation method that produces visually plausible muddy water effects. Muddy water is an example of suspension, which is a mixture containing particles that separate into distinct layers if left undisturbed. When stirred, however, the mud substance flows like a liquid and again begins settling out. Mud is composed of various sized particles and they produce different effects when it is blended with water. This thesis classifies the mud particles into three types and proposes different simulation methods for the types.