Predicting the response of liquefied natural gas(LNG)contained in vessels subjected to external waves is extremely important to ensure the safety of the transportation process.In this study,the coupled behavior due to...Predicting the response of liquefied natural gas(LNG)contained in vessels subjected to external waves is extremely important to ensure the safety of the transportation process.In this study,the coupled behavior due to ship motion and liquid tank sloshing has been simulated by the Smoothed-Particle Hydrodynamics(SPH)method.Firstly,the sloshing flow in a rectangular tank was simulated and the related loads were analyzed to verify and validate the accuracy of the present SPH solver.Then,a three-dimensional simplified LNG carrier model,including two prismatic liquid tanks and a wave tank,was introduced.Different conditions were examined corresponding to different wave lengths,wave heights,wave heading angles,and tank loading rates.Finally,the effects of liquid tank loading rate on LNG ship motions and sloshing loading were analyzed,thereby showing that the SPH method can effectively provide useful indications for the design of liquid cargo ships.展开更多
A coupled method describing gas–solid two-phase flow has been proposed to numerically study the bubble formation at a single orifice in gas-fluidized beds.Solid particles are traced with smoothed particle hydrodynami...A coupled method describing gas–solid two-phase flow has been proposed to numerically study the bubble formation at a single orifice in gas-fluidized beds.Solid particles are traced with smoothed particle hydrodynamics,whereas gas phase is discretized by finite volume method.Drag force,gas pressure gradient,and volume fraction are used to couple the two methods.The effect of injection velocities,particle sizes,and particle densities on bubble growth is analyzed using the coupled method.The simulation results,obtained for two-dimensional geometries,include the shape and diameter size of a bubble as a function of time;such results are compared with experimental data,previous numerical results,and other approximate model predictions reported in the literature.Moreover,the flow profiles of gas and particle phases and the temperature distribution by the heat transfer model around the forming bubble are also discussed.All results show that the coupled method efficiently describes of the bubble formation in fluidized beds.The proposed method is applicable for solving gas–solid two-phase flow in fluidization.展开更多
Particle based methods can be used for both the simulations of solid and fluid phases in multiphase medium, such as the discrete-element method for solid phase and the smoothed particle hydrodynamics for fluid phase. ...Particle based methods can be used for both the simulations of solid and fluid phases in multiphase medium, such as the discrete-element method for solid phase and the smoothed particle hydrodynamics for fluid phase. This paper presents a computational method combining these two methods for solid-liquid medium. The two phases are coupled by using an improved model from a reported Lagrangian-Eulerian method. The technique is verified by simulating liquid-solid flows in a two-dimensional lid-driven cavity.展开更多
Numerical simulation of the morphology of a droplet deposited on a solid surface requires an efficient description of the three-phase contact line. In this study, a simple method of implementing the contact angle is p...Numerical simulation of the morphology of a droplet deposited on a solid surface requires an efficient description of the three-phase contact line. In this study, a simple method of implementing the contact angle is proposed, combined with a robust smoothed particle hydrodynamics multiphase algorithm (Zhang 2015). The first step of the method is the creation of the virtual liquid-gas interface across the solid surface by means of dummy particles, thus the calculated surface tension near the triple point serves to automatically modulate the dynarnic contact line towards the equilibrium state. We simulate the evolution process of initially square liquid lumps on fiat and curved surfaces. The predictions of droplet profiles are in good agreement with the analytical solutions provided that the macroscopic contact angle is accurately implemented. Compared to the normal correction method, the present method is straightforward without the need to manually alter the normal vectors. This study presents a robust algorithm capable of capturing the physics of the static welling. It may hold great potentials in bio-inspired superhydrophobic surfaces, oil displacement, microfluidics, ore floatation, etc.展开更多
The faults in welding design and process every so often yield defective parts during friction stir welding(FSW).The development of numerical approaches including the finite element method(FEM)provides a way to draw a ...The faults in welding design and process every so often yield defective parts during friction stir welding(FSW).The development of numerical approaches including the finite element method(FEM)provides a way to draw a process paradigm before any physical implementation.It is not practical to simulate all possible designs to identify the optimal FSW practice due to the inefficiency associated with concurrent modeling of material flow and heat dissipation throughout the FSW.This study intends to develop a computational workflow based on the mesh-free FEM framework named smoothed particle hydrodynamics(SPH)which was integrated with adaptive neuro-fiizzy inference system(ANFIS)to evaluate the residual stress in the FSW process.An integrated SPH and ANFIS methodology was established and the well-trained ANIS was then used to predict how the FSW process depends on its parameters.To verify the SPH calculation,an itemized FSW case was performed on AZ91 Mg alloy and the induced residual stress was measured by ultrasonic testing.The suggested methodology can efficiently predict the residual stress distribution throughout friction stir welding of AZ91 alloy.展开更多
Submarine landslides can cause severe damage to marine engineering structures. Their sliding velocity and runout distance are two major parameters for quantifying and analyzing the risk of submarine landslides.Current...Submarine landslides can cause severe damage to marine engineering structures. Their sliding velocity and runout distance are two major parameters for quantifying and analyzing the risk of submarine landslides.Currently, commercial calculation programs such as BING have limitations in simulating underwater soil movements. All of these processes can be consistently simulated through a smoothed particle hydrodynamics(SPH) depth integrated model. The basis of the model is a control equation that was developed to take into account the effects of soil consolidation and erosion. In this work, the frictional rheological mode has been used to perform a simulation study of submarine landslides. Time-history curves of the sliding body's velocity, height,and length under various conditions of water depth, slope gradient, contact friction coefficient, and erosion rate are compared; the maximum sliding distance and velocity are calculated; and patterns of variation are discussed.The findings of this study can provide a reference for disaster warnings and pipeline route selection.展开更多
This paper extends the SPH method to gas simulation. The SPH (Smoothed Particles Hydrodynamics) method is the most popular method of flow simulation, which is widely used in large-scale liquid simulation. However, i...This paper extends the SPH method to gas simulation. The SPH (Smoothed Particles Hydrodynamics) method is the most popular method of flow simulation, which is widely used in large-scale liquid simulation. However, it is not found to apply to gas simulation, since those methods based on SPH can't be used in real-time simulation due to their enormous particles and huge computation. This paper proposes a method for gas simulation based on SPH with a small number of particles. Firstly, the method computes the position and density of each particle in each point-in-time, and outlines the shape of the simulated gas based on those particles. Secondly the method uses the grid technique to refine the shape with the diffusion of particle's density under the control of grid, and get more lifelike simulation result. Each grid will be assigned density according to the particles in it. The density determines the final appearance of the grid. For ensuring the natural transition of the color between adjacent grids, we give a diffuse process of density between these grids and assign appropriate values to vertexes of these grids. The experimental results show that the proposed method can give better gas simulation and meet the request of real-time.展开更多
When investigating water flow in spillways and energy dissipation, it is important to know the behavior of the free surfaces. To capture the real dynamic behavior of the free surfaces is therefore crucial when perform...When investigating water flow in spillways and energy dissipation, it is important to know the behavior of the free surfaces. To capture the real dynamic behavior of the free surfaces is therefore crucial when performing simulations. Today, there is a lack in the possibility to model such phenomenon with traditional methods. Hence, this work focuses on a parameter study for one alternative simulation tool available, namely the meshfree, Lagrangian particle method Smoothed Particle Hydrodynamics (SPH). The parameter study includes the choice of equation-of-state (EOS), the artificial viscosity constants, using a dynamic versus a static smoothing length, SPH particle spatial resolution and the finite element method (FEM) mesh scaling of the boundaries. The two dimensional SPHERIC Benchmark test case of dam break evolution over a wet bed was used for comparison and validation. The numerical results generally showed a tendency of the wave front to be ahead of the experimental results, i.e. to have a greater wave front velocity. The choice of EOS, FEM mesh scaling as well as using a dynamic or a static smoothing length showed little or no significant effect on the outcome, though the SPH particle resolution and the choice of artificial viscosity constants had a major impact. A high particle resolution increased the number of flow features resolved for both choices of artificial viscosity constants, but at the expense of increasing the mean error. Furthermore, setting the artificial viscosity constants equal to unity for the coarser cases resulted in a highly viscous and unphysical solution, and thus the relation between the artificial viscosity constants and the particle resolution and its impact on the behavior of the fluid needed to be further investigated.展开更多
随着电子设备日益微型化和集成化,热仿真已成为其设计中的关键因素。电子封装模块的热仿真通常使用传统的有限元法FEM(finite element method),存在计算效率和精度之间的矛盾,在处理大变形问题和网格畸变方面也容易造成计算不收敛,从而...随着电子设备日益微型化和集成化,热仿真已成为其设计中的关键因素。电子封装模块的热仿真通常使用传统的有限元法FEM(finite element method),存在计算效率和精度之间的矛盾,在处理大变形问题和网格畸变方面也容易造成计算不收敛,从而导致结果错误。针对该问题,提出一种基于光滑粒子动力学SPH(smoothed particle hydrodynamics)算法的电子封装模块热仿真系统。该算法基于无网格拉格朗日数值方法,通过将热仿真对象离散为1组粒子的方式求解热传导方程,从而准确地预测电子封装模块的传热与散热,无需生成并处理大量的微小网格,不用担心网格失真等问题。SPH相对于FEM,仿真精度误差保持在1%~2%,仿真效率可提升近30倍,适合用于复杂和动态系统的模拟仿真。展开更多
Fluid-structure interaction(FSI) is a class of mechanics-related problems with mutual dependence between the fluid and structure parts and it is observable nearly everywhere, in natural phenomena to many engineering s...Fluid-structure interaction(FSI) is a class of mechanics-related problems with mutual dependence between the fluid and structure parts and it is observable nearly everywhere, in natural phenomena to many engineering systems. The primary challenges in developing numerical models with conventional grid-based methods are the inherent nonlinearity and timedependent nature of FSI, together with possible large deformations and moving interfaces. Smoothed particle hydrodynamics(SPH) method is a truly Lagrangian and meshfree particle method that conveniently treats large deformations and naturally captures rapidly moving interfaces and free surfaces. Since its invention, the SPH method has been widely applied to study different problems in engineering and sciences, including FSI problems. This article presents a review of the recent developments in SPH based modeling techniques for solving FSI-related problems. The basic concepts of SPH along with conventional and higher order particle approximation schemes are first introduced. Then, the implementation of FSI in a pure SPH framework and the hybrid approaches of SPH with other grid-based or particle-based methods are discussed. The SPH models of FSI problems with rigid, elastic and flexible structures, with granular materials, and with extremely intensive loadings are demonstrated. Some discussions on several key techniques in SPH including the balance of accuracy, stability and efficiency, the treatment of material interface, the coupling of SPH with other methods, and the particle regularization and adaptive particle resolution are provided as concluding marks.展开更多
Violent free surface flows with strong fluid-solid interactions can produce a tremendous pressure load on structures, resu- lting in elastic and even plastic deformations. Modeling hydro-elastic problems with structur...Violent free surface flows with strong fluid-solid interactions can produce a tremendous pressure load on structures, resu- lting in elastic and even plastic deformations. Modeling hydro-elastic problems with structure deformations and a free surfaee breakup is difficult by using routine numerical methods. This paper presents an improved Smoothed Particle Hydrodynamics (SPH) method for modeling hydro-elastic problems. The fluid particles are used to model the free surface flows governed by Navier-Stokes equations, and the solid particles are used to model the dynamic movement and deformation of the elastic solid objects. The improved SPH method employs a Kernel Gradient Correction (KGC) technique to improve the computational accuracy and a Fluid-Solid Interface Treatment (FSIT) algorithm with the interface fluid and solid particles being treated as the virtual particles against their counterparts and a soft repulsive force to prevent the penetration and a corrective density approximation scheme to remove the numerical oscillations. Three typical numerical examples are simulated, including a head-on collision of two rubber rings, the dam break with an elastic gate and the water impact onto a forefront elastic plate. The obtained SPH results agree well with experimental observations and numerical results from other sources.展开更多
The purpose of the present paper is to introduce a simple two-part multi-phase model for the sediment transport problems based on the incompressible smoothed particle hydrodynamics(ISPH) method. The proposed model s...The purpose of the present paper is to introduce a simple two-part multi-phase model for the sediment transport problems based on the incompressible smoothed particle hydrodynamics(ISPH) method. The proposed model simulates the movement of sediment particles in two parts. The sediment particles are classified into three categories, including the motionless particles, moving particles behave like a rigid body, and moving particles with a pseudo fluid behavior. The criterion for the classification of sediment particles is the Bingham rheological model. Verification of the present model is performed by simulation of the dam break waves on movable beds with different conditions and the bed scouring under steady flow condition. Comparison of the present model results, the experimental data and available numerical results show that it has good ability to simulate flow pattern and sediment transport.展开更多
The 2017 SPHERIC Beijing International Workshop(or SPHERIC Beijing 2017) was held at Peking University, in China,on October 17-20, 2017. This is the first time that the SPHERIC Workshop was held out of Europe. We ar...The 2017 SPHERIC Beijing International Workshop(or SPHERIC Beijing 2017) was held at Peking University, in China,on October 17-20, 2017. This is the first time that the SPHERIC Workshop was held out of Europe. We are delighted to present nine contributions in this Special Column of the Journal of Hydrodynamics, and take this opportunity to announce that the 13 th SPHERIC Workshop(or SPHERIC 2018) will be held in Galway, Ireland in 2018 by the National University of Ireland, and the SPHERIC International Workshop in Harbin, China in 2019 by the Harbin Engineering University.展开更多
Since its inception,the full Lagrangian meshless smoothed particle hydrodynamics(SPH)has experienced a tremendous enhancement in methodology and impacted a range of multi-physics applications in science and engineerin...Since its inception,the full Lagrangian meshless smoothed particle hydrodynamics(SPH)has experienced a tremendous enhancement in methodology and impacted a range of multi-physics applications in science and engineering.This review presents a concise survey on latest developments and achievements of the SPH method,including:(1)Brief review of theory and fundamental with kernel corrections,(2)The Riemann-based SPH method with dissipation limiting and high-order data reconstruction by using MUSCL,WENO and MOOD schemes,(3)Particle neighbor searching with particle sorting and efficient dual-criteria time stepping schemes,(4)Total Lagrangian formulation with stablized,dynamics relaxation and hourglass control schemes,(5)Fluid-structure interaction scheme with interface treatments and multi-resolution discretizations,(6)Novel applications of particle relaxation in SPH methodology for mesh and particle generations.Last but not least,benchmark tests for validating computational accuracy,convergence,robustness and efficiency are also supplied accordingly.展开更多
基金the National Natural Science Foundation of China(No.52271316)the Guangdong Basic and Applied Basic Research Foundation(No.2023A1515030262).
文摘Predicting the response of liquefied natural gas(LNG)contained in vessels subjected to external waves is extremely important to ensure the safety of the transportation process.In this study,the coupled behavior due to ship motion and liquid tank sloshing has been simulated by the Smoothed-Particle Hydrodynamics(SPH)method.Firstly,the sloshing flow in a rectangular tank was simulated and the related loads were analyzed to verify and validate the accuracy of the present SPH solver.Then,a three-dimensional simplified LNG carrier model,including two prismatic liquid tanks and a wave tank,was introduced.Different conditions were examined corresponding to different wave lengths,wave heights,wave heading angles,and tank loading rates.Finally,the effects of liquid tank loading rate on LNG ship motions and sloshing loading were analyzed,thereby showing that the SPH method can effectively provide useful indications for the design of liquid cargo ships.
基金The support of National Nature Science Foundation of China(No.51276192)No.61338 for the National Basic Research Program of Chinathe Innovative Research Project of Xi’an Hi-tech Institute(EPXY0806)are gratefully acknowledged.
文摘A coupled method describing gas–solid two-phase flow has been proposed to numerically study the bubble formation at a single orifice in gas-fluidized beds.Solid particles are traced with smoothed particle hydrodynamics,whereas gas phase is discretized by finite volume method.Drag force,gas pressure gradient,and volume fraction are used to couple the two methods.The effect of injection velocities,particle sizes,and particle densities on bubble growth is analyzed using the coupled method.The simulation results,obtained for two-dimensional geometries,include the shape and diameter size of a bubble as a function of time;such results are compared with experimental data,previous numerical results,and other approximate model predictions reported in the literature.Moreover,the flow profiles of gas and particle phases and the temperature distribution by the heat transfer model around the forming bubble are also discussed.All results show that the coupled method efficiently describes of the bubble formation in fluidized beds.The proposed method is applicable for solving gas–solid two-phase flow in fluidization.
基金supported by Department of Energy and Process Engineering,Norwegian University of Science and TechnologyInstitute for Energy Technology and SINTEF through the FACE(Multiphase Flow Assurance Innovation Center) Project
文摘Particle based methods can be used for both the simulations of solid and fluid phases in multiphase medium, such as the discrete-element method for solid phase and the smoothed particle hydrodynamics for fluid phase. This paper presents a computational method combining these two methods for solid-liquid medium. The two phases are coupled by using an improved model from a reported Lagrangian-Eulerian method. The technique is verified by simulating liquid-solid flows in a two-dimensional lid-driven cavity.
基金by the National NaturalScience Foundation of China (Grants 11672335 and 11611530541)China Postdoctoral Science Foundation (Grant 2017M622307)+2 种基金ShandongNatural Science Foundation (Grant ZR201709210320)FundamentalResearch Funds for the Central Universities (Grant18CX0213A)the Endeavour Australia Cheung Kong ResearchFellowship Scholarship from the Australian government.
文摘Numerical simulation of the morphology of a droplet deposited on a solid surface requires an efficient description of the three-phase contact line. In this study, a simple method of implementing the contact angle is proposed, combined with a robust smoothed particle hydrodynamics multiphase algorithm (Zhang 2015). The first step of the method is the creation of the virtual liquid-gas interface across the solid surface by means of dummy particles, thus the calculated surface tension near the triple point serves to automatically modulate the dynarnic contact line towards the equilibrium state. We simulate the evolution process of initially square liquid lumps on fiat and curved surfaces. The predictions of droplet profiles are in good agreement with the analytical solutions provided that the macroscopic contact angle is accurately implemented. Compared to the normal correction method, the present method is straightforward without the need to manually alter the normal vectors. This study presents a robust algorithm capable of capturing the physics of the static welling. It may hold great potentials in bio-inspired superhydrophobic surfaces, oil displacement, microfluidics, ore floatation, etc.
文摘The faults in welding design and process every so often yield defective parts during friction stir welding(FSW).The development of numerical approaches including the finite element method(FEM)provides a way to draw a process paradigm before any physical implementation.It is not practical to simulate all possible designs to identify the optimal FSW practice due to the inefficiency associated with concurrent modeling of material flow and heat dissipation throughout the FSW.This study intends to develop a computational workflow based on the mesh-free FEM framework named smoothed particle hydrodynamics(SPH)which was integrated with adaptive neuro-fiizzy inference system(ANFIS)to evaluate the residual stress in the FSW process.An integrated SPH and ANFIS methodology was established and the well-trained ANIS was then used to predict how the FSW process depends on its parameters.To verify the SPH calculation,an itemized FSW case was performed on AZ91 Mg alloy and the induced residual stress was measured by ultrasonic testing.The suggested methodology can efficiently predict the residual stress distribution throughout friction stir welding of AZ91 alloy.
基金The Specialized Research Fund for the Doctoral Program of Higher Education under contract No.20120041130002the National Key Project of Science and Technology under contract No.2011ZX 05056-001-02the Fundamental Research Funds for the Central Universities under contract No.DUT14ZD220
文摘Submarine landslides can cause severe damage to marine engineering structures. Their sliding velocity and runout distance are two major parameters for quantifying and analyzing the risk of submarine landslides.Currently, commercial calculation programs such as BING have limitations in simulating underwater soil movements. All of these processes can be consistently simulated through a smoothed particle hydrodynamics(SPH) depth integrated model. The basis of the model is a control equation that was developed to take into account the effects of soil consolidation and erosion. In this work, the frictional rheological mode has been used to perform a simulation study of submarine landslides. Time-history curves of the sliding body's velocity, height,and length under various conditions of water depth, slope gradient, contact friction coefficient, and erosion rate are compared; the maximum sliding distance and velocity are calculated; and patterns of variation are discussed.The findings of this study can provide a reference for disaster warnings and pipeline route selection.
基金Supported by National Natural Science Foundation of China(No.61272024)
文摘This paper extends the SPH method to gas simulation. The SPH (Smoothed Particles Hydrodynamics) method is the most popular method of flow simulation, which is widely used in large-scale liquid simulation. However, it is not found to apply to gas simulation, since those methods based on SPH can't be used in real-time simulation due to their enormous particles and huge computation. This paper proposes a method for gas simulation based on SPH with a small number of particles. Firstly, the method computes the position and density of each particle in each point-in-time, and outlines the shape of the simulated gas based on those particles. Secondly the method uses the grid technique to refine the shape with the diffusion of particle's density under the control of grid, and get more lifelike simulation result. Each grid will be assigned density according to the particles in it. The density determines the final appearance of the grid. For ensuring the natural transition of the color between adjacent grids, we give a diffuse process of density between these grids and assign appropriate values to vertexes of these grids. The experimental results show that the proposed method can give better gas simulation and meet the request of real-time.
文摘When investigating water flow in spillways and energy dissipation, it is important to know the behavior of the free surfaces. To capture the real dynamic behavior of the free surfaces is therefore crucial when performing simulations. Today, there is a lack in the possibility to model such phenomenon with traditional methods. Hence, this work focuses on a parameter study for one alternative simulation tool available, namely the meshfree, Lagrangian particle method Smoothed Particle Hydrodynamics (SPH). The parameter study includes the choice of equation-of-state (EOS), the artificial viscosity constants, using a dynamic versus a static smoothing length, SPH particle spatial resolution and the finite element method (FEM) mesh scaling of the boundaries. The two dimensional SPHERIC Benchmark test case of dam break evolution over a wet bed was used for comparison and validation. The numerical results generally showed a tendency of the wave front to be ahead of the experimental results, i.e. to have a greater wave front velocity. The choice of EOS, FEM mesh scaling as well as using a dynamic or a static smoothing length showed little or no significant effect on the outcome, though the SPH particle resolution and the choice of artificial viscosity constants had a major impact. A high particle resolution increased the number of flow features resolved for both choices of artificial viscosity constants, but at the expense of increasing the mean error. Furthermore, setting the artificial viscosity constants equal to unity for the coarser cases resulted in a highly viscous and unphysical solution, and thus the relation between the artificial viscosity constants and the particle resolution and its impact on the behavior of the fluid needed to be further investigated.
文摘随着电子设备日益微型化和集成化,热仿真已成为其设计中的关键因素。电子封装模块的热仿真通常使用传统的有限元法FEM(finite element method),存在计算效率和精度之间的矛盾,在处理大变形问题和网格畸变方面也容易造成计算不收敛,从而导致结果错误。针对该问题,提出一种基于光滑粒子动力学SPH(smoothed particle hydrodynamics)算法的电子封装模块热仿真系统。该算法基于无网格拉格朗日数值方法,通过将热仿真对象离散为1组粒子的方式求解热传导方程,从而准确地预测电子封装模块的传热与散热,无需生成并处理大量的微小网格,不用担心网格失真等问题。SPH相对于FEM,仿真精度误差保持在1%~2%,仿真效率可提升近30倍,适合用于复杂和动态系统的模拟仿真。
基金supported by the National Natural Science Foundation of China(Grant No.51779003)the National Key Research and Development Project of China(Grant No.2018YFB0704000)
文摘Fluid-structure interaction(FSI) is a class of mechanics-related problems with mutual dependence between the fluid and structure parts and it is observable nearly everywhere, in natural phenomena to many engineering systems. The primary challenges in developing numerical models with conventional grid-based methods are the inherent nonlinearity and timedependent nature of FSI, together with possible large deformations and moving interfaces. Smoothed particle hydrodynamics(SPH) method is a truly Lagrangian and meshfree particle method that conveniently treats large deformations and naturally captures rapidly moving interfaces and free surfaces. Since its invention, the SPH method has been widely applied to study different problems in engineering and sciences, including FSI problems. This article presents a review of the recent developments in SPH based modeling techniques for solving FSI-related problems. The basic concepts of SPH along with conventional and higher order particle approximation schemes are first introduced. Then, the implementation of FSI in a pure SPH framework and the hybrid approaches of SPH with other grid-based or particle-based methods are discussed. The SPH models of FSI problems with rigid, elastic and flexible structures, with granular materials, and with extremely intensive loadings are demonstrated. Some discussions on several key techniques in SPH including the balance of accuracy, stability and efficiency, the treatment of material interface, the coupling of SPH with other methods, and the particle regularization and adaptive particle resolution are provided as concluding marks.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11172306,11232012 and81271650)the New Century Excellent Talents(Grant No.NCET-10-0041)the 100 Talents Programme of the Chinese Academy of Sciences
文摘Violent free surface flows with strong fluid-solid interactions can produce a tremendous pressure load on structures, resu- lting in elastic and even plastic deformations. Modeling hydro-elastic problems with structure deformations and a free surfaee breakup is difficult by using routine numerical methods. This paper presents an improved Smoothed Particle Hydrodynamics (SPH) method for modeling hydro-elastic problems. The fluid particles are used to model the free surface flows governed by Navier-Stokes equations, and the solid particles are used to model the dynamic movement and deformation of the elastic solid objects. The improved SPH method employs a Kernel Gradient Correction (KGC) technique to improve the computational accuracy and a Fluid-Solid Interface Treatment (FSIT) algorithm with the interface fluid and solid particles being treated as the virtual particles against their counterparts and a soft repulsive force to prevent the penetration and a corrective density approximation scheme to remove the numerical oscillations. Three typical numerical examples are simulated, including a head-on collision of two rubber rings, the dam break with an elastic gate and the water impact onto a forefront elastic plate. The obtained SPH results agree well with experimental observations and numerical results from other sources.
文摘The purpose of the present paper is to introduce a simple two-part multi-phase model for the sediment transport problems based on the incompressible smoothed particle hydrodynamics(ISPH) method. The proposed model simulates the movement of sediment particles in two parts. The sediment particles are classified into three categories, including the motionless particles, moving particles behave like a rigid body, and moving particles with a pseudo fluid behavior. The criterion for the classification of sediment particles is the Bingham rheological model. Verification of the present model is performed by simulation of the dam break waves on movable beds with different conditions and the bed scouring under steady flow condition. Comparison of the present model results, the experimental data and available numerical results show that it has good ability to simulate flow pattern and sediment transport.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11742012,51779003 and U1530110)
文摘The 2017 SPHERIC Beijing International Workshop(or SPHERIC Beijing 2017) was held at Peking University, in China,on October 17-20, 2017. This is the first time that the SPHERIC Workshop was held out of Europe. We are delighted to present nine contributions in this Special Column of the Journal of Hydrodynamics, and take this opportunity to announce that the 13 th SPHERIC Workshop(or SPHERIC 2018) will be held in Galway, Ireland in 2018 by the National University of Ireland, and the SPHERIC International Workshop in Harbin, China in 2019 by the Harbin Engineering University.
基金This work was supported by the Deutsche Forschungsgemeinschaft(DFG)(Grant No.HU1527/12-4)。
文摘Since its inception,the full Lagrangian meshless smoothed particle hydrodynamics(SPH)has experienced a tremendous enhancement in methodology and impacted a range of multi-physics applications in science and engineering.This review presents a concise survey on latest developments and achievements of the SPH method,including:(1)Brief review of theory and fundamental with kernel corrections,(2)The Riemann-based SPH method with dissipation limiting and high-order data reconstruction by using MUSCL,WENO and MOOD schemes,(3)Particle neighbor searching with particle sorting and efficient dual-criteria time stepping schemes,(4)Total Lagrangian formulation with stablized,dynamics relaxation and hourglass control schemes,(5)Fluid-structure interaction scheme with interface treatments and multi-resolution discretizations,(6)Novel applications of particle relaxation in SPH methodology for mesh and particle generations.Last but not least,benchmark tests for validating computational accuracy,convergence,robustness and efficiency are also supplied accordingly.