Incompressible smoothed particle hydrodynamics (SPH) with reduced temporal noise and generalised Fickian smoothing applied to body-water slam and efficient wave-body interaction
Incompressible smoothed particle hydrodynamics (SPH) with reduced temporal noise and generalised Fickian smoothing applied to body-water slam and efficient wave-body interaction
复制标题
不可压缩平滑粒子流体动力学 (SPH)，具有降低的时间噪声和广义 Fickian 平滑，应用于体水撞击和有效的波体相互作用
DOI：
10.1016/j.cma.2013.05.017
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发表时间：
2013
影响因子：
7.2
通讯作者：
Skillen A
中科院分区：
文献类型：
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作者：
Skillen A
不可压缩的平滑粒子流体力学通常需要粒子分布平滑，以给出稳定和准确的无噪声压力模拟。Lind等人的基于扩散的平滑算法。(J.Comp.太棒了。231(2012)1499-1523)已被证明对一系列脉冲流和传播波有效。在这里，我们将其应用于体-水冲击和波体碰撞问题，并发现在这些应用中可能会出现时间压力噪声(同时空间噪声被有效地消除)。这是由于自由表面处理为不连续边界所致。将其视为压力解算器内的连续的非常薄的边界被证明有效地解决了这个问题。对粒子平滑算法作了进一步的推广，采用了适合给定时间步长和粒子间距的无量纲扩散系数。我们模拟了圆柱体和楔体在静止水中的特殊问题。我们还通过在几个波长长的周期域内建立未受干扰的波传播并插入波体来模拟波体碰撞。在这种情况下，载荷在一个波周期后变为循环，与实验结果吻合较好。这种方法比传统的波浪水槽方法更有效，因为传统的波浪水槽方法需要多个波长和海滩吸波体，结果准确且几乎没有噪声，无论在空间上还是在时间上。证明了算法的收敛特性。虽然这些测试用例是具有简单几何结构的二维测试用例，但该方法是非常通用的，并且可以很容易地扩展到三维。
Incompressible smoothed particle hydrodynamics generally requires particle distribution smoothing to give stable and accurate simulations with noise-free pressures. The diffusion-based smoothing algorithm of Lind et al. (J. Comp. Phys. 231 (2012) 1499–1523) has proved effective for a range of impulsive flows and propagating waves. Here we apply this to body–water slam and wave–body impact problems and discover that temporal pressure noise can occur for these applications (while spatial noise is effectively eliminated). This is due to the free-surface treatment as a discontinuous boundary. Treating this as a continuous very thin boundary within the pressure solver is shown to effectively cure this problem. The particle smoothing algorithm is further generalised so that a non-dimensional diffusion coefficient is applied which suits a given time step and particle spacing.We model the particular problems of cylinder and wedge slam into still water. We also model wave-body impact by setting up undisturbed wave propagation within a periodic domain several wavelengths long and inserting the body. In this case, the loads become cyclic after one wave period and are in good agreement with experiment. This approach is more efficient than the conventional wave flume approach with a wavemaker which requires many wavelengths and a beach absorber.Results are accurate and virtually noise-free, spatially and temporally. Convergence is demonstrated. Although these test cases are two-dimensional with simple geometries, the approach is quite general and may be readily extended to three dimensions.