scholarly journals Incompressible SPH Model for Simulating Violent Free-Surface Fluid Flows

2014 ◽  
Vol 61 (1-2) ◽  
pp. 61-83
Author(s):  
Ryszard Staroszczyk
Keyword(s):  
Free Surface ◽  
Vertical Wall ◽  
Fluid Motion ◽  
Time History ◽  
Particle Hydrodynamics ◽  
Sph Model ◽  
History Of ◽  
Smoothed Particle ◽  
Incompressibility Constraint ◽  
The Impact

Abstract In this paper the problem of transient gravitational wave propagation in a viscous incompressible fluid is considered, with a focus on flows with fast-moving free surfaces. The governing equations of the problem are solved by the smoothed particle hydrodynamics method (SPH). In order to impose the incompressibility constraint on the fluid motion, the so-called projection method is applied in which the discrete SPH equations are integrated in time by using a fractional-step technique. Numerical performance of the proposed model has been assessed by comparing its results with experimental data and with results obtained by a standard (weakly compressible) version of the SPH approach. For this purpose, a plane dam-break flow problem is simulated, in order to investigate the formation and propagation of a wave generated by a sudden collapse of a water column initially contained in a rectangular tank, as well as the impact of such a wave on a rigid vertical wall. The results of simulations show the evolution of the free surface of water, the variation of velocity and pressure fields in the fluid, and the time history of pressures exerted by an impacting wave on a wall.

scholarly journals Numerical Simulation of Non-Homogeneous Viscous Debris-Flows Based on the Smoothed Particle Hydrodynamics (SPH) Method

Water ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2314 ◽  
Author(s):  
Shu Wang ◽  
Anping Shu ◽  
Matteo Rubinato ◽  
Mengyao Wang ◽  
Jiping Qin
Keyword(s):  
Debris Flow ◽  
Water Content ◽  
Smoothed Particle Hydrodynamics ◽  
Debris Flows ◽  
Sph Method ◽  
Particle Hydrodynamics ◽  
Sph Model ◽  
Smoothed Particle ◽  
The Impact ◽  
Kinetic And Potential Energies

Non-homogeneous viscous debris flows are characterized by high density, impact force and destructiveness, and the complexity of the materials they are made of. This has always made these flows challenging to simulate numerically, and to reproduce experimentally debris flow processes. In this study, the formation-movement process of non-homogeneous debris flow under three different soil configurations was simulated numerically by modifying the formulation of collision, friction, and yield stresses for the existing Smoothed Particle Hydrodynamics (SPH) method. The results obtained by applying this modification to the SPH model clearly demonstrated that the configuration where fine and coarse particles are fully mixed, with no specific layering, produces more fluctuations and instability of the debris flow. The kinetic and potential energies of the fluctuating particles calculated for each scenario have been shown to be affected by the water content by focusing on small local areas. Therefore, this study provides a better understanding and new insights regarding intermittent debris flows, and explains the impact of the water content on their formation and movement processes.

scholarly journals Modelling of tsunami wave run-up, breaking and impact on vertical wall by SPH method

2013 ◽  
Vol 1 (3) ◽  
pp. 2831-2857
Author(s):  
M. H. Dao ◽  
H. Xu ◽  
E. S. Chan ◽  
P. Tkalich
Keyword(s):  
Wave Breaking ◽  
Vertical Wall ◽  
Sph Method ◽  
Particle Hydrodynamics ◽  
Potential Applications ◽  
Sph Model ◽  
Smoothed Particle ◽  
Run Up ◽  
Steep Waves ◽  
Tunami N2

Abstract. Accurate predictions of wave run-up and run-down are important for coastal impact assessment of relatively long waves such as tsunami or storm waves. Wave run-up is, however, a complex process involving nonlinear build-up of the wave front, intensive wave breaking and strong turbulent flow, making the numerical approximation challenging. Recent advanced modeling methodologies could help to overcome these numerical challenges. For a demonstration, we study run-up of non-breaking and breaking solitary waves on vertical wall using two methods, the enhanced Smoothed Particle Hydrodynamics (SPH) method and the traditional non-breaking nonlinear model Tunami-N2. The Tunami-N2 model fails to capture the evolution of steep waves at the proximity of breaking that observed in the experiments. Whereas, the SPH method successfully simulate the wave propagation, breaking, impact on structure and the reform and breaking processes of wave run-down. The study also indicates that inadequate approximation of the wave breaking could lead to significant under-predictions of wave height and impact pressure on structures. The SPH model shows potential applications for accurate impact assessments of wave run-up onto coastal structures.

Fluid-Structure Interaction Simulation With Free Surface Flows by Smoothed Particle Hydrodynamics

2008 ◽  
Author(s):  
M. H. Farahani ◽  
N. Amanifard ◽  
H. Asadi ◽  
M. Mahnama
Keyword(s):  
Free Surface ◽  
Fluid Structure Interaction ◽  
Free Surface Flows ◽  
Surface Flows ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Incompressibility Constraint ◽  
Sph Algorithm

Simulation of the fluid-structure interaction (FSI) and free surface flows includes an area of extremely challenging problems in the computational mechanics community. In this paper, a newly proposed SPH algorithm is employed to simulate FSI problems with complex free surface flows. In this way, fluid and elastic structure continua are coupled using a monolithic but explicit numerical scheme. The proposed method is similar to so-called SPH projection method and consists of three steps. The first two steps play the role of prediction, while in the third step a Poisson equation is used for both fluid and structure to impose incompressibility constraint.

A Development of a SPH Model for Simulating Surface Erosion by Impact(s) of Irregularly Shaped Particles

2018 ◽  
Vol 15 (08) ◽  
pp. 1850074 ◽  
Author(s):  
Xiangwei Dong ◽  
Zengliang Li ◽  
Zirui Mao ◽  
Tao Lin
Keyword(s):  
Erosive Wear ◽  
Ductile Material ◽  
Surface Erosion ◽  
Mesh Free ◽  
Particle Hydrodynamics ◽  
Sph Model ◽  
Smoothed Particle ◽  
Erosion Mechanisms ◽  
The Impact ◽  
Angular Particles

Modeling and studying the impact of angular particles are very helpful in understanding the fundamental mechanisms of erosive wear. However, the majority of previous studies focused on well-defined symmetrical particles, which are not well representative of the abrasive particles. Hence, this study develops a mesh-free model based on the smoothed particle hydrodynamics (SPH) method to simulate impact(s) of single and multiple irregularly shaped particles on ductile material. A novel procedure is proposed to model the particle as a polygonal rigid body through measuring the corner vertices. Simulations are carried out by varying the input conditions and by using different types of angular particles. Common erosion mechanisms such as cutting, machining, ploughing, prying-off are successfully reproduced by the model. The predicted crater is compared with available experimental data, and good agreement has been achieved. The proposed SPH model and out present study could be useful in the study of erosive wear on the surface of metal devices that carries granular substances.

scholarly journals Effects of Barrier Stiffness on Debris Flow Dynamic Impact—II: Numerical Simulation

Water ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 182
Author(s):  
Yu Huang ◽  
Xiaoyan Jin ◽  
Junji Ji
Keyword(s):  
Debris Flow ◽  
Smoothed Particle Hydrodynamics ◽  
Impact Force ◽  
Time History ◽  
Appreciable Effect ◽  
Engineering Structures ◽  
Dynamic Component ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
The Impact

The destructive and impactful forces of debris flow commonly causes local damage to engineering structures. The effect of a deformable barrier on the impact dynamics is important in engineering design. In this study, a flow–structure coupled with Smoothed Particle Hydrodynamics model was presented to investigate the effects of barrier stiffness on the debris impact. A comparison of the results of physical tests and simulation results revealed that the proposed smoothed particle hydrodynamics model effectively reproduces the flow kinematics and time history of the impact force. Even slight deflections of the deformable barrier lead to obvious attenuation of the peak impact pressure. Additionally, deformable barriers with lower stiffness tend to deform more downstream upon loading, shifting the deposited sand toward the active failure mode and generating less static earth pressure. When the debris flow has a higher frontal velocity, the impact force on the barrier is dominated by the dynamic component and there is an appreciable effect of the stiffness of the deformable barrier on load attenuation.

scholarly journals Modelling of tsunami-like wave run-up, breaking and impact on a vertical wall by SPH method

2013 ◽  
Vol 13 (12) ◽  
pp. 3457-3467 ◽  
Author(s):  
M. H. Dao ◽  
H. Xu ◽  
E. S. Chan ◽  
P. Tkalich
Keyword(s):  
Wave Breaking ◽  
Vertical Wall ◽  
Sph Method ◽  
Particle Hydrodynamics ◽  
Potential Applications ◽  
Sph Model ◽  
Smoothed Particle ◽  
Run Up ◽  
Steep Waves ◽  
Tunami N2

Abstract. Accurate predictions of wave run-up and run-down are important for coastal impact assessment of relatively long waves such as tsunami or storm waves. Wave run-up is, however, a complex process involving nonlinear build-up of the wave front, intensive wave breaking and strong turbulent flow, making the numerical approximation challenging. Recent advanced modelling methodologies could help to overcome these numerical challenges. For a demonstration, we study run-up of non-breaking and breaking solitary waves on a vertical wall using two methods, an enhanced smoothed particle hydrodynamics (SPH) method and the traditional non-breaking nonlinear model Tunami-N2. The Tunami-N2 model fails to capture the evolution of steep waves at the proximity of breaking that was observed in the experiments. Whereas the SPH method successfully simulates the wave propagation, breaking, impact on structure and the reform and breaking processes of wave run-down. The study also indicates that inadequate approximation of the wave breaking could lead to significant under-predictions of wave height and impact pressure on structures. The SPH model shows potential applications for accurate impact assessments of wave run-up on to coastal structures.

scholarly journals Smoothed Particle Hydrodynamics Modeling with Advanced Boundary Conditions for Two-Dimensional Dam-Break Floods

Water ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 1142
Author(s):  
Domenica Mirauda ◽  
Raffaele Albano ◽  
Aurelia Sole ◽  
Jan Adamowski
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
Numerical Solutions ◽  
Vertical Wall ◽  
Dam Break ◽  
Secondary Wave ◽  
Two Dimensional ◽  
Boundary Treatment ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
The Impact

To simulate the dynamics of two-dimensional dam-break flow on a dry horizontal bed, we use a smoothed particle hydrodynamics model implementing two advanced boundary treatment techniques: (i) a semi-analytical approach, based on the computation of volume integrals within the truncated portions of the kernel supports at boundaries and (ii) an extension of the ghost-particle boundary method for mobile boundaries, adapted to free-slip conditions. The trends of the free surface along the channel, and of the impact wave pressures on the downstream vertical wall, were first validated against an experimental case study and then compared with other numerical solutions. The two boundary treatment schemes accurately predicted the overall shape of the primary wave front advancing along the dry bed until its impact with the downstream vertical wall. Compared to data from numerical models in the literature, the present results showed a closer fit to an experimental secondary wave, reflected by the downstream wall and characterized by complex vortex structures. The results showed the reliability of both the proposed boundary condition schemes in resolving violent wave breaking and impact events of a practical dam-break application, producing smooth pressure fields and accurately predicting pressure and water level peaks.

Numerical Simulation of Die Swell of Second-Order Fluids Using Smoothed Particle Hydrodynamics

2010 ◽  
Author(s):  
Samir Hassan Sadek ◽  
Mehmet Yildiz
Keyword(s):  
Free Surface ◽  
Smoothed Particle Hydrodynamics ◽  
Second Order ◽  
Rheological Parameters ◽  
Die Swell ◽  
Two Dimensional ◽  
Polymeric Fluid ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Second Order Fluids

This work presents the development of both weakly compressible and incompressible Smoothed Particle Hydrodynamics (SPH) models for simulating two-dimensional transient viscoelastic free surface flow which has extensive applications in polymer processing industries. As an illustration with industrial significance, we have chosen to model the extrudate swell of a second-order polymeric fluid. The extrudate or die swell is a phenomenon that takes place during the extrusion of polymeric fluids. When a polymeric fluid is forced through a die to give a polymer its desired shape, due to its viscoelastic non-Newtonian nature, it shows a tendency to swell or contract at the die exit depending on its rheological parameters. The die swell phenomenon is a typical example of a free surface problem where the free surface is formed at the die exit after the polymeric fluid has been extruded. The swelling process leads to an undesired increase in the dimensions of the extrudate. To be able to obtain a near-net shape product, the flow in the extrusion process should be well-understood to shed some light on the important process parameters behind the swelling phenomenon. To this end, a systematic study has been carried out to compare constitutive models proposed in literature for second-order fluids in terms of their ability to capture the physics behind the swelling phenomenon. The effect of various process and rheological parameters on the die swell such as the extrusion velocity, normal stress coefficients, and Reynolds and Deborah numbers have also been investigated. The models developed here can predict both swelling and contraction of the extrudate successfully. The die swell problem was solved for a wide range of Deborah numbers and for two different Re numbers. The numerical model was validated through the solution of fully developed Newtonian and Non-Newtonian viscoelastic flows in a two-dimensional channel, and the results of these two benchmark problems were compared with analytic solutions, and good agreements were obtained.

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