复杂场景流固耦合的高效模拟

High Effective Simulation of Solid-Fluid Coupling for Complex Scenes

大规模复杂流体场景的高效交互模拟技术在灾难仿真、虚拟现实和影视特效制作等领域都有重要的应用价值.针对现有基于物理的流体算法大多只适于尺度较小的场景,难以有效地模拟复杂流体大场景中流固耦合时的固体破碎效果的问题,提出一种复杂场景的固液耦合高效模拟方法.首先提出一种基于流体隐式粒子法和散度为零的SPH法相混合的计算框架,在确保流体物理属性的同时充分利用细粒度的隐式粒子来丰富流体运动细节,提高场景模拟的真实感;然后采用一种多维度的流固耦合分合计算策略来进一步提高流固耦合效率;为实现流体冲击下的固体破碎效果,采用一种物理与几何相混合的破碎方法:以基于断裂力学中的应变能密度模型来确定固体破碎时碎片的分布,采用基于几何的质心Voronoi方法快速生成碎片,最终实现百万量级粒子参与的复杂流体场景的交互模拟,以及高速流体冲击下的固体破碎效果的高效模拟.

Efficient simulation techniques of large-scale complex solid-fluid coupling scenes have been found widely applications in the areas such as disaster simulation,virtual reality and film and TV special effect manufacture,etc.However,current physical based fluid simulation algorithms can only simulate small scale scenes and fail to effectively simulate the solid fracture effect in large-scale complex solid-fluid coupling scenes.To overcome this defect,in this paper we proposed an efficient solid-fluid method for complex scenes to improve.First,we presented a new calculation framework which combines divergence free smoothed particle hydrodynamics(DFSPH)method and fluid implicit particle(FLIP)method,which fully utilizes the advantage of fine grained implicit particles to add the dynamic details of fluid scenes.This improved the realism of simulated scenes while keeping the physical attributes of fluid.Then,we hired a multi-dimension divide-and-recombine solid-fluid coupling calculation framework to further enhance solid-fluid coupling efficiency.To realize the solid fracture effect under fluid lashing,a physical and geometrical hybrid method was used:Strain energy density model in fracture mechanics was hired to determine fragment distribution during solid fracture process,while geometrical based centroid Voronoi diagram method was hired to rapidly generate fragments.Finally,large-scale complex solid-fluid coupling scenes with millions of parwith millions of particles participating in are successfully simulated interactively,including the efficient simulation of solid fracture effect under lashing of high speed fluid.