Incompressible smoothed particle hydrodynamics for free-surface flows: A generalised diffusion-based algorithm for stability and validations for impulsive flows and propagating waves
Incompressible smoothed particle hydrodynamics for free-surface flows: A generalised diffusion-based algorithm for stability and validations for impulsive flows and propagating waves
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DOI：
10.1016/j.jcp.2011.10.027
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发表时间：
2012-02-20
影响因子：
4.1
通讯作者：
Rogers, B. D.
中科院分区：
文献类型：
--
作者：
Lind, S. J.;Xu, R.;Rogers, B. D.
具有基于投影的压力校正的不可压缩平滑粒子流体动力学（ISPH）方法已经被证明对于内部流是高度精确和稳定的，并且对于许多问题来说重要的是，与弱可压缩SPH方法相比，压力场几乎是无噪声的（Xu等人，2009 [31]）。然而，几乎无粘流体的不稳定性在自由表面发生由于与截断内核的错误。提出了一种新的算法，解决了这个问题，提供稳定和准确的解决方案，内部和自由表面流动。推广Xu等人的粒子移动方法。（2009）[31]，该算法基于Fick扩散定律，并以防止高度各向异性分布和数值不稳定性的方式移动粒子。该算法是验证对内部流的解析解在较高的雷诺数比以前，由于一个冲动开始板和高精度的解决方案，湿床溃坝问题在零和小的时间流。然后，该方法进行了验证的渐进规则波与桨运动定义的线性理论。准确的预测表明，该算法在稳定的解决方案，并尽量减少与截断内核的不可避免的错误所产生的表面不稳定性的有效性。测试案例被认为提供了比以前进行的更彻底的定量验证。(C)2011 Elsevier Inc. All rights reserved.
The incompressible smoothed particle hydrodynamics (ISPH) method with projection-based pressure correction has been shown to be highly accurate and stable for internal flows and, importantly for many problems, the pressure field is virtually noise-free in contrast to the weakly compressible SPH approach (Xu et al., 2009 [31]). However for almost inviscid fluids instabilities at the free surface occur due to errors associated with the truncated kernels. A new algorithm is presented which remedies this issue, giving stable and accurate solutions to both internal and free-surface flows. Generalising the particle shifting approach of Xu et al. (2009) [31], the algorithm is based upon Fick's law of diffusion and shifts particles in a manner that prevents highly anisotropic distributions and the onset of numerical instability. The algorithm is validated against analytical solutions for an internal flow at higher Reynolds numbers than previously, the flow due to an impulsively started plate and highly accurate solutions for wet bed dam break problems at zero and small times. The method is then validated for progressive regular waves with paddle motion defined by linear theory. The accurate predictions demonstrate the effectiveness of the algorithm in stabilising solutions and minimising the surface instabilities generated by the inevitable errors associated with truncated kernels. The test cases are thought to provide a more thorough quantitative validation than previously undertaken. (C) 2011 Elsevier Inc. All rights reserved.