A multi-scale model for simulating liquid-hair interactions
A multi-scale model for simulating liquid-hair interactions
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DOI：
10.1145/3072959.3073630
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发表时间：
2017-07
期刊：
影响因子：
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通讯作者：
Yun Fei;H. Maia;Christopher Batty;Changxi Zheng;E. Grinspun
中科院分区：
文献类型：
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作者：
Yun Fei;H. Maia;Christopher Batty;Changxi Zheng;E. Grinspun
头发与液体之间的多种相互作用复杂且涉及多个长度尺度，但在很多情况下对人类和动物的外观至关重要。因此，我们提出了一种新颖的多组件模拟框架，该框架处理了许多控制湿头发动力学的关键物理机制。我们方法的基础是头发的离散杆模型和流体的粒子在单元模型。为了处理附着在头发上的液体薄层，我们为每根头发丝增加了一个高度场表示。我们的贡献是开发必要的物理和数值模型来演化这个新系统及其组件之间的相互作用。我们开发了一种新的降维液体模型，以解决液体沿着每根头发长度的运动问题，同时考虑其移动参考系以及对头发动力学的影响。我们基于连接相邻头发的液桥几何形状，推导出了一个能准确描述表面张力引起的相邻头发之间内聚效应的模型。我们采用一个经实验验证的阻力模型来处理头发与周围流体之间的粗尺度相互作用的影响，并提出新的体积守恒的滴落和吸收策略，以便在降维和粒子在单元液体表示之间转移液体。这些技术的综合产生了一个有效的湿头发模拟器，我们用它来模拟头发翻转、动物甩干自己、旋转的洗车滚刷浸入液体以及复杂的头发聚并效果等多个其他场景。
The diverse interactions between hair and liquid are complex and span multiple length scales, yet are central to the appearance of humans and animals in many situations. We therefore propose a novel multi-component simulation framework that treats many of the key physical mechanisms governing the dynamics of wet hair. The foundations of our approach are a discrete rod model for hair and a particle-in-cell model for fluids. To treat the thin layer of liquid that clings to the hair, we augment each hair strand with a height field representation. Our contribution is to develop the necessary physical and numerical models to evolve this new system and the interactions among its components. We develop a new reduced-dimensional liquid model to solve the motion of the liquid along the length of each hair, while accounting for its moving reference frame and influence on the hair dynamics. We derive a faithful model for surface tension-induced cohesion effects between adjacent hairs, based on the geometry of the liquid bridges that connect them. We adopt an empirically-validated drag model to treat the effects of coarse-scale interactions between hair and surrounding fluid, and propose new volume-conserving dripping and absorption strategies to transfer liquid between the reduced and particle-in-cell liquid representations. The synthesis of these techniques yields an effective wet hair simulator, which we use to animate hair flipping, an animal shaking itself dry, a spinning car wash roller brush dunked in liquid, and intricate hair coalescence effects, among several additional scenarios.