Lagrangian Gridless Model of Toe Scouring of Seawall Due to Tsunami Return Flow

Hayashi, Minoru; Gotoh, Hitoshi; Sakai, Tetsuo; Ikari, Hiroyuki

doi:10.1142/9789812703040_0059

Cited by 3 publications

(7 citation statements)

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“…By following Hayashi et al (2003) and Ikari et al (2010), both the normal and the tangential velocity components of the flow are used to evaluate the sediment initiation. The two flow velocities acting on a movable bed particle are obtained by interpolating the velocities of nearby inner fluid particles to this reference particle using the SPH kernel function, as follows (Ran et al, 2013):…”

Section: Fig 1 Different Types Of Particles Near Movable Bed In Isphmentioning

confidence: 99%

“…Equation (26) follows Hayashi et al (2003), in which collision F = fluid force on the bed surface and is assumed to be the self-weight of sediment grain under critical condition, m = mass of sediment grain and t  = computational time step.…”

Section: Fig 1 Different Types Of Particles Near Movable Bed In Isphmentioning

confidence: 99%

“…These methods have also been efficiently used to the dam break flows over erodible bed. For example, Hayashi et al (2003) used the Moving Particle Semi-implicit (MPS) method combined with a bed scour model based on erosion velocity to compute the seawall toe scouring due to a dropping jet. Shakibaeinia and Jin (2011) used the weakly compressible MPS formulation together with different rheological models to compute an unsteady dam break flow over movable bed.…”

Section: Introductionmentioning

confidence: 99%

“…In view of the existing SPH practice to model the mobile bed scouring, they generally fall into two distinct categories. One is to treat the water and sediment media as two different fluid components and an interaction model is used to address the discontinuity of the two phases (Shakibaeinia and Jin, 2011), while another is to consider the critical velocity and shear stress of the flow acting on the sediment bed and treat the bed as an erodible solid wall (Hayashi et al, 2003). The latter approach is explored in present paper as we think it could more realistically reflect the sediment erosion and scouring mechanism, which is consistent with the empirical sediment principles adopted by the engineering practice.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Incompressible SPH scour model for movable bed dam break flows

Ran

Tong

Shao

et al. 2015

Advances in Water Resources

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In this study an incompressible Smoothed Particle Hydrodynamics (ISPH) approach coupled with the sediment erosion model is developed to investigate the sediment bed scour and grain movement under the dam break flows. Two-phase formulations are used in the ISPH numerical algorithms to examine the free surface and bed evolution profiles, in which the entrained sediments are treated as a different fluid component as compared with the water. The sediment bed erosion model is based on the concept of pick-up flow velocity and the sediment is initiated when the local flow velocity exceeds a critical value. Also, a simple viscosity model is used to correct the fluid viscosity due to the mixing of the sediment materials with water. The proposed model is used to reproduce the sediment erosion and follow-on entrainment process under an instantaneous dam break flow and the results are compared with those from the weakly compressible Moving Particle Semi-implicit (WCMPS) method as well as the experimental data. It has been demonstrated that the two-phase ISPH model performed well with the experimental data. The study shows that the ISPH modelling approach can accurately predict the dynamic sediment scouring process without the need to use empirical sediment transport formulas.

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Section: Fig 1 Different Types Of Particles Near Movable Bed In Isphmentioning

confidence: 99%

Section: Fig 1 Different Types Of Particles Near Movable Bed In Isphmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Incompressible SPH scour model for movable bed dam break flows

Ran

Tong

Shao

et al. 2015

Advances in Water Resources

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“…In terms of existing SPH practice to model the sediment scouring, there are two different approaches: (1) Most of documented works treated the water and sediment as different fluid components and therefore, relevant interaction models are used to link the two phases (Shakibaeinia and Jin, 2011;Manenti et al, 2016); (2) The other approach, which will also be adopted in the present paper, considered the counterbalance between the fluid force and sediment bed resistance. As a result, either the critical velocity (Hayashi et al, 2003;Ran et al 2005) or the critical shear stress (Manenti et al, 2012) criterion can be used to determine the initiation of sediment particles when the threshold condition is satisfied. The purpose of present research is to develop a 3D ISPH sediment erosion model to study movable bed scours around a vertical circular cylinder.…”

Section: Introductionmentioning

confidence: 99%

3D ISPH erosion model for flow passing a vertical cylinder

Wang

Shao

et al. 2018

Journal of Fluids and Structures

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In this paper a 3D incompressible Smoothed Particle Hydrodynamics (ISPH) erosion model is proposed to simulate the scouring process behind a large vertical cylinder. The erosion model is based on the turbidity water particle concept and the sediment motion is initiated when the fluid bottom shear stress exceeds the critical value. The previous 2D SPH sediment initiation model is expanded by combining the effects of both transverse and longitudinal sloping beds in a practical 3D situation. To validate the developed model, a laboratory flume experiment was carried out to study the clear water scouring around a vertical cylinder under unidirectional current, in which high-speed video cameras were used for the real-time monitoring of sediment movement. The 3D ISPH results are compared with the experimental data with good agreement in terms of the scouring patterns and scales. Besides, the computed flow velocity field suggests that both the horseshoe vortices and lee-wake flows around the cylinder have been accurately simulated.

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Dynamic hydraulic jump and retrograde sedimentation in an open channel induced by sediment supply: experimental study and SPH simulation

et al. 2019

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Mountainous torrents often carry large amounts of loose materials into the rivers, thus causing strong sediment transport. Experimentally it was found for the first time that when the intensive sediment motion occurs downstream over a gentle slope, the siltation of the riverbed is induced and the sediment particles can move upstream rapidly in the form of a retrograde sand wave, resulting in a higher water level along the river. To further study the complex mechanisms of this problem, a sediment mass model in the framework of the Smoothed Particle Hydrodynamics (SPH) method was presented to simulate the riverbed evolution, sediment particle motion, and the generation and development of dynamic hydraulic jump under the condition of sufficient sediment supply over a steep slope with varying angles. Because the sediment is not a continuous medium, the marker particle tracking approach was proposed to represent a piece of sediment with a marked sediment particle. The two-phase SPH model realizes the interaction between the sediment and fluid by moving the bed boundary particles up and down, so it can reasonably treat the fluidsediment interfaces with high CPU efficiency. The critical triggering condition of sediment motion, the propagation of the hydraulic jump and the initial siltation position were all systematically studied. The experimental and numerical results revealed the extra disastrous sediment effect in a mountainous flood. The findings will be useful references to the disaster prevention and mitigation in mountainous rivers.

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Lagrangian Gridless Model of Toe Scouring of Seawall Due to Tsunami Return Flow

Cited by 3 publications

References 0 publications

Incompressible SPH scour model for movable bed dam break flows

Incompressible SPH scour model for movable bed dam break flows

3D ISPH erosion model for flow passing a vertical cylinder

Dynamic hydraulic jump and retrograde sedimentation in an open channel induced by sediment supply: experimental study and SPH simulation

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