The numerical modeling of a 2D flow around a horizontal cylinder near a rigid bed with the gap ratios G/D = 0, 0.2, 0.3 at Reynolds numbers 840, 4500, 9000, and 9500 is investigated by using weakly compressible smooth...The numerical modeling of a 2D flow around a horizontal cylinder near a rigid bed with the gap ratios G/D = 0, 0.2, 0.3 at Reynolds numbers 840, 4500, 9000, and 9500 is investigated by using weakly compressible smoothed particle hydrodynamics. The velocity field and the separation angles from the present simulations are compared with those obtained from the experimental measurements and are in a good agreement. The results show that the maximum value of shear stress on the bed increases as the cylinder closes the bed and suddenly decreases when the cylinder contact the wall.展开更多
The subject of present study is the application of mesh free Lagrangian two-dimensional non-cohesive sediment transport model applied to a two-phase flow over an initially trapezoidal-shaped sediment embankment. The g...The subject of present study is the application of mesh free Lagrangian two-dimensional non-cohesive sediment transport model applied to a two-phase flow over an initially trapezoidal-shaped sediment embankment. The governing equations of the present model are the Navier-Stocks equations solved using Weakly Compressible Smoothed Particle Hydrodynamics （WCSPH） method. To simulate the movement of sediment particles, the model considers a powerful two-part technique; when the sediment phase has rigid behavior, only the force term due to shear stress in the Navier-Stokes equations is used for simulation of sediment particles＇ movement. Otherwise, all the Navier-Stokes force terms are used for transport simulation of sediment particles. In the present model, the interactions between different phases are calculated automatically, even with considerable difference between the density and viscosity of phases. Validation of the model is performed using simulation of available laboratory experiments, and the comparison between computational results and experimental data shows that the model generally predicts well the flow propagation over movable beds, the induced sediment transport and bed changes, and temporal evolution of embankment breaching.展开更多
文摘The numerical modeling of a 2D flow around a horizontal cylinder near a rigid bed with the gap ratios G/D = 0, 0.2, 0.3 at Reynolds numbers 840, 4500, 9000, and 9500 is investigated by using weakly compressible smoothed particle hydrodynamics. The velocity field and the separation angles from the present simulations are compared with those obtained from the experimental measurements and are in a good agreement. The results show that the maximum value of shear stress on the bed increases as the cylinder closes the bed and suddenly decreases when the cylinder contact the wall.
文摘The subject of present study is the application of mesh free Lagrangian two-dimensional non-cohesive sediment transport model applied to a two-phase flow over an initially trapezoidal-shaped sediment embankment. The governing equations of the present model are the Navier-Stocks equations solved using Weakly Compressible Smoothed Particle Hydrodynamics （WCSPH） method. To simulate the movement of sediment particles, the model considers a powerful two-part technique; when the sediment phase has rigid behavior, only the force term due to shear stress in the Navier-Stokes equations is used for simulation of sediment particles＇ movement. Otherwise, all the Navier-Stokes force terms are used for transport simulation of sediment particles. In the present model, the interactions between different phases are calculated automatically, even with considerable difference between the density and viscosity of phases. Validation of the model is performed using simulation of available laboratory experiments, and the comparison between computational results and experimental data shows that the model generally predicts well the flow propagation over movable beds, the induced sediment transport and bed changes, and temporal evolution of embankment breaching.
