SPH体积映射流固交互的稳定性及细节提升方法

Stability and Detail Improvement Method for SPH Volume Maps Fluid-Solid Interaction

针对现有的光滑粒子流体动力学(SPH)流固交互方法中存在的稳定性以及流体细节表现不佳的问题,提出一种改进的体积映射流固交互方法.首先采用无散度SPH方法对流体进行建模,保证流体的不可压缩性;然后引入体积映射方法处理固体边界,以隐式函数的形式表示边界而无需使用粒子,解决粒子采样的固体表面不平滑的问题;再引入移动最小二乘法对固体边界上的压强进行插值,避免压强镜像带来的误差,提升体积映射方法中压强和压强梯度计算的精确性,提高系统的稳定性;最后引入粒子重采样方法进行流体表面细化,充分表现流体表面区域的不同粒子特征,增强流固交互后的流体细节,提高真实感.在斯坦福大学公开的基本三维模型上的实验结果表明,所提方法能够真实、稳定地表现不可压缩流体与固体的交互现象,处理多个静态或动态固体的复杂场景,并且能够有效地刻画流体细节.

Aiming at the stability problems and the poor fluid details of the existing smoothed particle hy-drodynamics(SPH)fluid-solid interaction methods,an improved fluid-solid interaction method based on volume maps was proposed.Firstly,the divergence-free SPH method was used to model the fluid to enforce the incompressibility.Secondly,the volume maps method was introduced to handle the solid boundary,and the boundary was represented by implicit functions instead of particles to solve the problem of the bumpy solid surface with particle sampling method.Thirdly,Moving Least Squares was introduced to interpolate the pressure on the solid boundary to avoid the error caused by the pressure mirroring,which improved the accuracy of the pressure and pressure gradient in the volume maps,and improved the system stability.Fi-nally,the particle resampling method was introduced to refine the fluid surface to fully show the different particle characteristics of the fluid surface regions,which enhanced the fluid details after fluid-solid interac-tion and the reality.The experiments used the basic three-dimensional models provided by Stanford Univer-sity.The experimental results show that this method can truly and stably simulate the interaction of incom-pressible fluids and solids,handle complex scenes with multiple static or dynamic solids,and effectively represent fluid details.