The hydrodynamic problem of a two-dimensional wedge entering water is studied based on Smoothed Particle Hydrodynamics （SPH） model. A non-reflection boundary treatment for SPH method is proposed to reduce the reflec...The hydrodynamic problem of a two-dimensional wedge entering water is studied based on Smoothed Particle Hydrodynamics （SPH） model. A non-reflection boundary treatment for SPH method is proposed to reduce the reflection of sound waves. The boundary pressure is obtained using an improved coupling boundary treatment approach, which is validated by comparing the simulation results with experimental and analytical results in literature. A series of cases with different initial entering velocities are simulated. The maximum force on the wedge and the corresponding time required to reach it for the different cases of initial entering velocities of the wedge are obained and fitted into formulas against the initial entering velocity of the wedge. The maximum drag coefficients of the wedge for the different cases with Froude number greater than 2 are all near the value of 0.91.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
Smoothed particle hydrodynamics （SPH） is a Lagrangian, meshfree particle method and has been widely applied to diffe- rent areas in engineering and science. Since its original extension to modeling free surface flow...Smoothed particle hydrodynamics （SPH） is a Lagrangian, meshfree particle method and has been widely applied to diffe- rent areas in engineering and science. Since its original extension to modeling free surface flows by Monaghan in 1994, SPH has been gradually developed into an attractive approach for modeling viscous incompressible fluid flows. This paper presents an overview on the recent progresses of SPH in modeling viscous incompressible flows in four major aspects which are closely related to the computational accuracy of SPH simulations. The advantages and disadvantages of different SPH particle approximation sche- mes, pressure field solution approaches, solid boundary treatment algorithms and particle adapting algorithms are described and analyzed. Some new perspectives and fuRtre trends in SPH modeling of viscous incompressible flows are discussed.展开更多
A numerical model was established for simulating water wave dynamic problems by adopting the Smoothed Particle Hydrodynamics （SPH） methods of iterative solution of Poisson＇s equation for pressure field, and meanwhi...A numerical model was established for simulating water wave dynamic problems by adopting the Smoothed Particle Hydrodynamics （SPH） methods of iterative solution of Poisson＇s equation for pressure field, and meanwhile the sub-grid turbulence model was applied in the simulation so as to more accurately describe the turbulence characteristics at the time of wave breaking. In this article, simulation of the problem of the dam collapsing verifies the compoting accuracy of this method, and its results can be identical with the results of VOF method and the experimental results by comparison. Numerical simulations of the course of solitary wave and cnoidal wave run-up breaking on beaches were conducted, and the results are basically consistent with experimental results This indicates that the SPH method is effective for the numerical simulation of the complex problems of water wave dynamics.展开更多
基金supported by the National Natural Science Foundation of China (Grant No.10802049)the Shanghai Leading Academic Discipline Project (Grant No.B206)the Research Found of State Key Laboratory of Ocean Engineering,Shanghai Jiao Tong University (Grant No.GKZD010806)
文摘The hydrodynamic problem of a two-dimensional wedge entering water is studied based on Smoothed Particle Hydrodynamics （SPH） model. A non-reflection boundary treatment for SPH method is proposed to reduce the reflection of sound waves. The boundary pressure is obtained using an improved coupling boundary treatment approach, which is validated by comparing the simulation results with experimental and analytical results in literature. A series of cases with different initial entering velocities are simulated. The maximum force on the wedge and the corresponding time required to reach it for the different cases of initial entering velocities of the wedge are obained and fitted into formulas against the initial entering velocity of the wedge. The maximum drag coefficients of the wedge for the different cases with Froude number greater than 2 are all near the value of 0.91.
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 Foun-dation of China(Grant Nos.11172306,U1530110)the Institu-te of Systems Engineering,China Academy of Engineering Physics(Grant No.2013KJZ01)
文摘Smoothed particle hydrodynamics （SPH） is a Lagrangian, meshfree particle method and has been widely applied to diffe- rent areas in engineering and science. Since its original extension to modeling free surface flows by Monaghan in 1994, SPH has been gradually developed into an attractive approach for modeling viscous incompressible fluid flows. This paper presents an overview on the recent progresses of SPH in modeling viscous incompressible flows in four major aspects which are closely related to the computational accuracy of SPH simulations. The advantages and disadvantages of different SPH particle approximation sche- mes, pressure field solution approaches, solid boundary treatment algorithms and particle adapting algorithms are described and analyzed. Some new perspectives and fuRtre trends in SPH modeling of viscous incompressible flows are discussed.
基金supported by the National High Techology Research and Development Program of China (863 Program,Grant No.2007AA11Z130)
文摘A numerical model was established for simulating water wave dynamic problems by adopting the Smoothed Particle Hydrodynamics （SPH） methods of iterative solution of Poisson＇s equation for pressure field, and meanwhile the sub-grid turbulence model was applied in the simulation so as to more accurately describe the turbulence characteristics at the time of wave breaking. In this article, simulation of the problem of the dam collapsing verifies the compoting accuracy of this method, and its results can be identical with the results of VOF method and the experimental results by comparison. Numerical simulations of the course of solitary wave and cnoidal wave run-up breaking on beaches were conducted, and the results are basically consistent with experimental results This indicates that the SPH method is effective for the numerical simulation of the complex problems of water wave dynamics.
