| 华云军,周晓敏,徐云卿,孙政.溃坝流冲击特性的B样条物质点法模拟研究[J].计算力学学报,2025,42(5):772~779 |
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| 溃坝流冲击特性的B样条物质点法模拟研究 |
| Study on the impact characteristics of dam-break flow based on the B-spline material point method |
| 投稿时间：2024-05-08 修订日期：2024-06-07 |
| DOI：10.7511/jslx20240508001 |
| 中文关键词: 溃坝流 冲击特性 B样条物质点法 接触算法 |
| 英文关键词:Dam-break flow impact pressure characterization B-spline material point method contact algorithm |
| 基金项目:国家自然科学基金(12262013;11902127);江西省自然科学基金杰出青年基金(20232ACB211005);江西省主要学科学术和技术带头人培养计划(20225BCJ23022)资助项目. |
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| 中文摘要: |
| 准确模拟溃坝的冲击特性对溃坝流灾害预测和防治具有重要意义。B样条物质点法作为物质点法的一种改进算法,有效提高了计算精度和改进了收敛性。然而,B样条物质点法基于张量网格而非欧拉背景网格进行控制方程的求解;同时,其插值形函数具有更大的影响域;因此,在求解流固耦合等接触问题时存在过早接触、接触界面不易捕捉、接触力难以计算等问题。在同一B样条物质点张量网格空间内,基于同一结点的相对速度以及单位外法线实现接触界面的准确捕捉;采用格列维尔公式(Greville Abscissa),实现接触物体的精准接触,避免过早或虚假接触;通过拉格朗日乘子法,准确判定界面接触力,构建采用流固统一描述的流固强耦合高精度接触算法,开展溃坝流体冲击刚性和弹性障碍物模拟研究,并与已有试验结果或模拟结果进行对比。结果表明,模拟所得冲击荷载及结构变形演化规律与已有试验结果/模拟结果吻合较好;对刚性障碍物,随水位高度和溃坝坡度的增大,冲击压力峰值分别呈现下凹型抛物增长和正相关指数函数增长;对弹性障碍物,冲击压力峰值随探测点高度的增大呈负相关指数函数递减。验证了基于B样条物质点法接触算法模拟溃坝流冲击问题的可行性和有效性,为模拟溃坝流冲击问题提供一种新视角。 |
| 英文摘要: |
| Accurately simulating the impact characteristics of a dam break is of paramount significance for the prediction and mitigation of dam-break flow disasters.The B-spline material point method(BSMPM),as an improved algorithm of the material point method(MPM),effectively enhances computational accuracy and improves convergence.However,the BSMPM solves the governing equations based on a tensor grid rather than an Eulerian background grid.Moreover,its interpolation shape functions have a larger influence domain.Consequently,when solving problems involving fluid-structure coupling and contact,issues such as premature contact,difficulty in capturing contact interfaces,and challenges in calculating contact forces arise.Within the same tensor grid space of the BSMPM,accurate capture of contact interfaces is achieved based on the relative velocities and unit outward normals of the same nodes;employing the Greville Abscissa enables precise contact of contacting objects,thereby avoiding premature or spurious contact;through the Lagrange multiplier method,interface contact forces are accurately determined,thus constructing a high-precision contact algorithm for fluid-structure strongly coupled problems,facilitating research on the simulation of dam-break fluid impact with rigid and elastic obstacles,and enabling a comparison with existing experimental or simulated results.The results demonstrate that the simulated impact loads and structural deformation evolution patterns correspond well with existing experimental/simulated results.For rigid obstacles,the peak impact pressure exhibits concave parabolic growth and positive correlation exponential function growth with increasing water level and dam-break slope,respectively.For elastic obstacles,the peak impact pressure decreases exponentially with the increase in the height of the probing point.The feasibility and effectiveness of simulating dam-break flow impact problems using the BSMPM contact algorithm are validated,providing a new perspective for simulating dam-break flow impact problems. |
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