The particle simulation method is used to solve free-surface slurry flow problems that may be encountered in several scientific and engineering fields.The main idea behind the use of the particle simulation method is ...The particle simulation method is used to solve free-surface slurry flow problems that may be encountered in several scientific and engineering fields.The main idea behind the use of the particle simulation method is to treat granular or other materials as an assembly of many particles.Compared with the continuum-mechanics-based numerical methods such as the finite element and finite volume methods,the movement of each particle is accurately described in the particle simulation method so that the free surface of a slurry flow problem can be automatically obtained.The major advantage of using the particle simulation method is that only a simple numerical algorithm is needed to solve the governing equation of a particle simulation system.For the purpose of illustrating how to use the particle simulation method to solve free-surface flow problems,three examples involving slurry flow on three different types of river beds have been considered.The related particle simulation results obtained from these three examples have demonstrated that:1) The particle simulation method is a promising and useful method for solving free-surface flow problems encountered in both the scientific and engineering fields;2) The shape and irregular roughness of a river bed can have a significant effect on the free surface morphologies of slurry flow when it passes through the river bed.展开更多
通过在界面标识方程中引入人工压缩项,采用基于非结构网格的高分辨率有界格式,编程实现了一类适合模拟复杂界面流问题的VOF(Volume of Fluid)方法.这类VOF方法可以自动处理界面的拓扑演化,无须进行实时的界面重构,提高了计算效率.应用...通过在界面标识方程中引入人工压缩项,采用基于非结构网格的高分辨率有界格式,编程实现了一类适合模拟复杂界面流问题的VOF(Volume of Fluid)方法.这类VOF方法可以自动处理界面的拓扑演化,无须进行实时的界面重构,提高了计算效率.应用这种基于有界压缩思想的界面流模拟方法,对三维Rayleigh-Taylor不稳定性问题进行了并行模拟.计算结果与相关文献的数据吻合较好,证明了算法的可靠性.研究了密度差和Reynolds数对界面演化的影响,分析了在不同Atwood数下鞍点结构演化规律的异同,对于Reynolds数小于282的界面流问题黏性起着很明显的作用,而Atwood数的影响限于低密度差的界面流动问题,即Atwood数小于0.90的情形.展开更多
应用流体体积法(Volume of Fluid,VOF)模型跟踪稳定器近水面拖动时的自由液面的变化,利用计算流体动力学软件FLUENT对线列阵稳定器近水面的阻力性能进行数值模拟,分析研究了近水面兴波对其阻力性能的影响。分别计算了在不同水深的静水...应用流体体积法(Volume of Fluid,VOF)模型跟踪稳定器近水面拖动时的自由液面的变化,利用计算流体动力学软件FLUENT对线列阵稳定器近水面的阻力性能进行数值模拟,分析研究了近水面兴波对其阻力性能的影响。分别计算了在不同水深的静水和有波浪载荷工况下近水面拖动时不同种类的线列阵稳定器的阻力大小,并将数值模拟的结果与水池实验结果进行对比。结果表明,稳定器在近水面无波和有波情况下的阻力大小均比深水域静水的阻力要大,而且在有波情况与相对浸深为0.3时的阻力性能基本相等。展开更多
在轴对称坐标系下,采用有限体积法求解液滴形成的N-S方程,运用Ansys 13.0中的VOF(Volume of Fluid)方法对重力作用下,流体在微管口液滴形成过程进行数值模拟,采用PLIC(Piecewise Linear Interface Construction)的几何重构方法成功捕捉...在轴对称坐标系下,采用有限体积法求解液滴形成的N-S方程,运用Ansys 13.0中的VOF(Volume of Fluid)方法对重力作用下,流体在微管口液滴形成过程进行数值模拟,采用PLIC(Piecewise Linear Interface Construction)的几何重构方法成功捕捉液滴形成、变化与脱落过程的气液交界面,得到与实验相一致的研究结果,表明建模方法可行。分析了速度对液滴运动过程的影响,在颈缩阶段,入流速度决定流体内部速度,轴线压力呈线性增加趋势;断裂阶段,重力决定流体内部速度,轴线压力与速度波动趋势一致,最后得到无量纲数A(液滴完整长度与管内径比)和We的关联式A 8.611 We 2.98。展开更多
为系统地分析无侧收缩折线型实用堰(简称折线堰)上游边坡系数对自由堰流流量系数的影响规律,采用VOF(volume of fluid method)方法和RNG k-ε紊流模型对下游边坡直立、上游边坡系数依次为0、0.3、0.5、0.8、1.0、1.5和2.0的7个折线堰模...为系统地分析无侧收缩折线型实用堰(简称折线堰)上游边坡系数对自由堰流流量系数的影响规律,采用VOF(volume of fluid method)方法和RNG k-ε紊流模型对下游边坡直立、上游边坡系数依次为0、0.3、0.5、0.8、1.0、1.5和2.0的7个折线堰模型进行数值模拟。数值模拟结果表明,随着堰顶总水头的增加,水面线曲率减小,流量系数增大,同时上游边坡系数对流量系数的影响逐渐减小。采用多元非线性回归方法建立了含有上游边坡系数的折线堰流量系数计算公式,该公式在堰顶总水头一定时,流量系数随着上游边坡系数先增大后减小。展开更多
基金Project(11272359)supported by the National Natural Science Foundation of China
文摘The particle simulation method is used to solve free-surface slurry flow problems that may be encountered in several scientific and engineering fields.The main idea behind the use of the particle simulation method is to treat granular or other materials as an assembly of many particles.Compared with the continuum-mechanics-based numerical methods such as the finite element and finite volume methods,the movement of each particle is accurately described in the particle simulation method so that the free surface of a slurry flow problem can be automatically obtained.The major advantage of using the particle simulation method is that only a simple numerical algorithm is needed to solve the governing equation of a particle simulation system.For the purpose of illustrating how to use the particle simulation method to solve free-surface flow problems,three examples involving slurry flow on three different types of river beds have been considered.The related particle simulation results obtained from these three examples have demonstrated that:1) The particle simulation method is a promising and useful method for solving free-surface flow problems encountered in both the scientific and engineering fields;2) The shape and irregular roughness of a river bed can have a significant effect on the free surface morphologies of slurry flow when it passes through the river bed.
文摘通过在界面标识方程中引入人工压缩项,采用基于非结构网格的高分辨率有界格式,编程实现了一类适合模拟复杂界面流问题的VOF(Volume of Fluid)方法.这类VOF方法可以自动处理界面的拓扑演化,无须进行实时的界面重构,提高了计算效率.应用这种基于有界压缩思想的界面流模拟方法,对三维Rayleigh-Taylor不稳定性问题进行了并行模拟.计算结果与相关文献的数据吻合较好,证明了算法的可靠性.研究了密度差和Reynolds数对界面演化的影响,分析了在不同Atwood数下鞍点结构演化规律的异同,对于Reynolds数小于282的界面流问题黏性起着很明显的作用,而Atwood数的影响限于低密度差的界面流动问题,即Atwood数小于0.90的情形.
文摘应用流体体积法(Volume of Fluid,VOF)模型跟踪稳定器近水面拖动时的自由液面的变化,利用计算流体动力学软件FLUENT对线列阵稳定器近水面的阻力性能进行数值模拟,分析研究了近水面兴波对其阻力性能的影响。分别计算了在不同水深的静水和有波浪载荷工况下近水面拖动时不同种类的线列阵稳定器的阻力大小,并将数值模拟的结果与水池实验结果进行对比。结果表明,稳定器在近水面无波和有波情况下的阻力大小均比深水域静水的阻力要大,而且在有波情况与相对浸深为0.3时的阻力性能基本相等。
文摘在轴对称坐标系下,采用有限体积法求解液滴形成的N-S方程,运用Ansys 13.0中的VOF(Volume of Fluid)方法对重力作用下,流体在微管口液滴形成过程进行数值模拟,采用PLIC(Piecewise Linear Interface Construction)的几何重构方法成功捕捉液滴形成、变化与脱落过程的气液交界面,得到与实验相一致的研究结果,表明建模方法可行。分析了速度对液滴运动过程的影响,在颈缩阶段,入流速度决定流体内部速度,轴线压力呈线性增加趋势;断裂阶段,重力决定流体内部速度,轴线压力与速度波动趋势一致,最后得到无量纲数A(液滴完整长度与管内径比)和We的关联式A 8.611 We 2.98。
文摘为系统地分析无侧收缩折线型实用堰(简称折线堰)上游边坡系数对自由堰流流量系数的影响规律,采用VOF(volume of fluid method)方法和RNG k-ε紊流模型对下游边坡直立、上游边坡系数依次为0、0.3、0.5、0.8、1.0、1.5和2.0的7个折线堰模型进行数值模拟。数值模拟结果表明,随着堰顶总水头的增加,水面线曲率减小,流量系数增大,同时上游边坡系数对流量系数的影响逐渐减小。采用多元非线性回归方法建立了含有上游边坡系数的折线堰流量系数计算公式,该公式在堰顶总水头一定时,流量系数随着上游边坡系数先增大后减小。
