Coupling Smoothed Particle Hydrodynamics Research Articles

Numerical Simulation of Subaerial Granular Landslide Impulse Waves and Their Behaviour on a Slope Using a Coupled Smoothed Particle Hydrodynamics–Discrete Element Method

Numerical simulations were conducted to investigate the wave features of subaerial granular landslide-generated impulse waves and their impact on slopes. A numerical solution was obtained by coupling smoothed particle hydrodynamics (SPH) and the discrete element method (DEM). Several predictive equations were tested for their applicability in predicting the maximum crest amplitude of impulse waves generated by slides of different shapes. The results indicated that the predictive model developed by Heller and Hager, utilising slide centroid impact velocity, showed favourable prediction accuracy for the maximum crest amplitude, almost independent of the slide shape at impact. Regarding the leading wave, although the wave profile and velocity distribution deviated significantly from a solitary wave of the same wave amplitude, the maximum run-up could be satisfactorily estimated using solitary wave theory. In addition, the increase in the maximum dynamic forces exerted by the impulse waves on the slope followed a power law with the incident wave amplitude.

Blasting effects of the borehole considering decoupled eccentric charge

The investigation of the blasting effects of the borehole considering decoupled eccentric charge is scarce and lacks thorough exploration. The coupled Smoothed Particle Hydrodynamics and Finite Element Method (SPH-FEM) is adopted to study the decoupled eccentric charge blasting effects. The effective stress distribution of rock around the borehole is analyzed and the damage evolution is studied quantitatively with introducing image recognition algorithm. Further, the effect of the decoupling coefficient on blasting effects is investigated. Results show that effective stress distribution presents obvious eccentric characteristics. At the bottom coupling point, the maximum effective stress is observed, and gradually reduces towards the top uncoupling point. The lower part of rock surrounding the borehole exhibits a higher damaged area ratio compared to the upper part for decoupled eccentric charge blasting. With the decoupling coefficient increases from 1.14 to 2.00, the effective stresses at monitoring points are all decreasing and the effective stress ratio first increases and then keeps relatively stable, with the decoupling coefficient of 1.6 as inflection point. As the decoupling coefficient increases to 1.6, the damage extent ratio reaches the peak. The greatest disparity in explosion energy between the coupled and uncoupled sides occurs at a decoupling coefficient of approximately 1.6.

A modified SPH framework of for simulating progressive rock damage and water inrush disasters in tunnel constructions

To date, numerically simulating the Fluid–Solid Interaction (FSI) and the entire process of host rock damage and water inrush involved in tunnel construction relies intensively on hybrid methods of two or more numerical codes, which commonly encounter deficiency in learning, modelling and computation. A modified framework of Smoothed Particle Hydrodynamics (SPH), the Coupled Discontinuous SPH (CDSPH) method, was developed to simulate cracking, contacting and large deformation of rock blocks, free surface flow and the FSI for water/mud inrush disasters in tunnel construction through water–rich stratums. The failed SPH particles were transformed to discontinuous particles and new contacts between these particles were formed to simulate the frictional slip and separation/compression between fracture walls. The improved SPH method was employed to a water inrush case of a tunnel and the simulation results indicate that the entire process of progressive rock damage, water inrush and flooding are precisely reproduced by the improved method. The greater kinematic viscosity of fluids and rock wall thickness can increase the flow velocity and hence increasing the impact pressure of floods, and the failure pattern of the rock wall changes from partial outburst to complete failure. Vulnerability analysis of the water inrush reveals a complete damage status for people, vehicles and Non-RC frame buildings, and a moderate to complete damage to RC frame buildings at the tunnel portal. This single code is capable of simulating the behaviour of rocks, fluids and their interactions in catastrophic disasters that is potentially applicable to a wide spectrum of surface and subsurface problems involving FSI.

Morphological damage to tungsten eroded by abrasive water jet

Abrasive water jet is a promising method for processing rolled tungsten plates, which are considered the most promising plasma-facing material in fusion devices. To investigate the erosion of tungsten due to the abrasive water jet, we conducted erosion tests and numerical simulations. We examined the morphological characteristics of the tungsten erosion damage. An erosion model was developed by coupling smoothed-particle hydrodynamics with the finite-element method to simulate tungsten erosion. The mechanism behind the morphological damage characteristics of tungsten was analyzed. Our findings reveal that as erosion depth increases, the kinetic energy of the abrasive particles decreases while the erosion angle increases. The erosion damage to tungsten transitions from brittle fracture induced by microcutting and microplowing to impact deformation. As a result, the erosion section's morphology deteriorates, exhibiting strips from the cutting process, increasing both the trailing angle and surface roughness. The morphological damage characteristics of tungsten are intricately linked to the abrasive particles' motion. Therefore, by altering the motion characteristics of these particles, the erosion section's quality can be enhanced. This research offers valuable insights for enhancing the quality of tungsten sections processed by abrasive water jets in fusion devices.

Coupling SPH with a mesh-based Eulerian approach for simulation of incompressible free-surface flows

This paper presents a coupling algorithm for the simulation of incompressible free-surface flows over the near and far fields by solving the Navier-Stokes equations. The coupling combines the Smoothed Particle Hydrodynamics (SPH) with the Finite Difference (FD) method implemented on structured Eulerian grids. Based on the domain decomposition, the SPH is applied to the near-field core region for modeling with high-fidelity the severe free-surface deformation and even fragmentation of flow, while the FD method is used to resolve the remaining far-field region with relatively high efficiency. The primary purpose of the hybrid approach is to mitigate the computational load of SPH applications through combination with a mesh-based Eulerian method while maintaining high accuracy for both the near-field and far-field simulations. Two-way coupling between the FD and SPH models is achieved by the overlapping region between the computational subdomains, in which the Eulerian solutions and the Lagrangian solutions are coupled with each other through interpolation in the overlapping region for the fluid transfer and free-surface movement between the near-field and far-field regions. The proposed algorithm is validated by several test cases, showing favorable accuracy, convergence, and applicability in the simulation of wave interactions with complex bathymetry and structures.

Numerical Simulation of the Large‐Scale Huangtian (China) Landslide‐Generated Impulse Waves by a GPU‐Accelerated Three‐Dimensional Soil‒Water Coupled SPH Model

AbstractThis work presents an improved soil‒water coupling model to simulate landslide‐generated impulse waves (LGIWs) in a unified smoothed particle hydrodynamics (SPH) framework, where both water flow and landslide motions are modeled by SPH using an interface coupling technique. Graphics processing unit technology based on an open‐source platform DualSPHysics is chosen to employ the landslide dynamics and soil‒water interface coupling to achieve the capability of large‐scale simulation and high‐resolution modeling for three‐dimensional LGIW problems. A subaerial landslide‐generated water waves, is simulated to demonstrate the accuracy and ability of this model. The Huangtian LGIW is then simulated to reproduce the entire disaster chain, including landslide dynamics, fluid‒solid interaction, and surge wave generation. Particle resolution dependence is examined, giving a particle distance of 5.0 m, which can provide a converged landslide deposit and surge wave. The simulation shows that in the Huangtian LGIW, the landslide deposit volume was approximately 41.6 million m3 (600 m width, 768 m length, and 400 m above the still water level), with an immersed landslide volume of 11.3 million m3; for the surge wave, the maximum wave and run‐up heights were 34.3 and 48 m, respectively. These results are within the estimated ranges of both the landslide and surge wave according to limited field survey data. The case study of the Huangtian LGIW provides a typical reference of how to reproduce a reliable whole process of large scale multi‐physical and multiscale LGIW, including full information of landslide dynamics, interface coupling behavior, and surge wave characteristics.

A GPU-accelerated adaptive particle refinement for multi-phase flow and fluid-structure coupling SPH

In this paper, a graphical processing unit (GPU) implementation of adaptive particle refinement (APR) in the Smoothed Particle Hydrodynamics (SPH) framework is used to simulate the multi-phase flow and fluid-structure coupling problems. The multi-phase flow and fluid-structure coupling SPH models based on the Riemann solver are presented and the local particle refinement technique based on the axis-aligned square refinement pattern is adopted to split particles. A particle shifting technique constructing virtual fine particles (VFP-PST) is proposed to regularize the particle distribution for numrical accuracy and stability. To facilitate the device memory throughput efficiently, a dynamic resource management algorithm is used to implement GPU-accelerated adaptive particle refinement. Precision analysis shows the effect of the smooth length ratio of fine and coarse particles on numerical accuracy. Different tests have demonstrated that the proposed GPU-accelerated IAPR is accurate and stable and provides a promising approach to simulate the multi-phase flow and fluid-structure problems with low computational cost and comparable precision when compared with uniform particles.

Coupled smoothed particle hydrodynamics and discrete element method for simulating coarse food particles in a non-Newtonian conveying fluid

A Lagrangian particle-based numerical framework based on smoothed particle hydrodynamics (SPH) coupled with a discrete element method (DEM) was used to simulate the flow behavior of coarse food particles in a non-Newtonian conveying fluid in a horizontal pipe. Nearly neutrally buoyant nearly spherical calcium-alginate particles were used as model food particles. The capability of the SPH–DEM methodology was successfully validated in non-Newtonian single-phase as well as in two-phase particle–liquid flows by comparing the local phase velocity flow field, radial particle distribution, and particle passage times with experimental Lagrangian measurements obtained by a technique of positron emission particle tracking. The simulations also yielded accurate predictions of flow pressure drop. In addition, detailed information was afforded on local particle spin, fluid pressure, and carrier fluid vorticity. The results demonstrate the high capability of the proposed numerical framework to predict the complex features of complex particle–liquid flows in pipes.

Two-particle method for liquid–solid two-phase mixed flow

Liquid–solid two-phase flows are a very important class of multiphase flow problems widely existing in industry and nature. This paper establishes a two-phase model for liquid–solid two-phase flows considering multiphase states of granular media. The volume fraction is defined by the solid phase, determining the material properties of the two phases, and momentum is exchanged between the phases by drag and pressure gradient forces. On this basis, a two-particle method for simulating the liquid–solid two-phase flow is proposed by coupling smoothed particle hydrodynamics with smoothed discrete particle hydrodynamics. The coupling framework for the two-particle method is constructed, and the coupling between the algorithms is realized through interphase momentum exchange, volume fraction constraint, and field variable sharing. The liquid phase density changes are divided into two types. One is caused by weak compressibility, and the other is caused by changes in the solid phase volume fraction. The former is used to calculate the liquid-phase flow field, and the latter is used to calculate the two-phase coupling to solve the problem of sudden bulk density changes in the liquid phase caused by changes in particle volume fractions. The two-particle method maintains the dual advantages of the particle method for free interface tracking and material point tracking for particles. The new method is validated using a series of fundamental test cases, and comparison with experimental results shows that the new method is suitable for resolving liquid–solid two-phase flow problems and has significant practical value for future simulations of mudflow motions, coastal breakwaters, and landslide surges.

Mechanisms of pop-up delamination in laminated composites pierced by the initial pure waterjet in abrasive waterjet machining

The entrainment abrasive waterjet machines start with a pure waterjet before abrasives are injected to avoid nozzle clogging. This pure waterjet impact is the primary cause for delamination in the form of edge pop-up of laminated composites. This paper presents an investigation into the pop-up delamination formation mechanisms. A coupled fluid–solid numerical model is developed by coupling smoothed particle hydrodynamics method and finite element method. It is found that pop-up delamination is initiated due to the material’s elastic response to a rapid release of shock pressure to stagnation pressure and the traverse shear stresses induced by the bending of the plies. A hydro wedging effect between the plies due to flow divergence propagates the delamination. There is a threshold value for the water pressure above which pop-up delamination does not increase significantly. Moreover, the smallest delamination area takes place on the [0]12 composite, followed by the [0/45/90/-45/0/45]s and [0/90]3s composites.

Coupling of an IOT wear sensor and numerical modelling in predicting wear evolution of a slurry pump

Slurry pump is an integral system between upstream and downstream mineral processing circuit to transport product streams. It is critical to monitor the slurry pump liner wear to ensure safe and efficient circuit operation, as well as achieving targeted product quality. This study aims to develop a digital wear sensor to monitor slurry pump liner wear and to predict its wear evolution by coupling to a numerical modelling framework. The digital sensor is designed to track and report live point-wise thickness on a slurry pump liner while in operation. A liner wear evolution model was then developed by integrating the wear sensor reading and wear intensity results obtained through numerical modelling. The wear intensity was obtained by coupling Smoothed Particle Hydrodynamics and Discrete Element Modelling. Liner wear evolution prediction results were subsequently compared with site measurements after operating for 95 days. Results suggested that the liner wear evolution prediction showed good agreements with measured results in terms of high wear zone as well as quantitative wear rate prediction. Outcome of this study can be utilised in mineral processing industry for safer operation as well as automated plant monitoring.

In-depth analysis of hydroplaning phenomenon accounting for tire wear on smooth ground

Studying hydroplaning behavior is of crucial importance in order to enhance driver safety and mitigate the environmental impact as it is estimated that about 128 million tires are replaced prematurely each year. It is therefore necessary to take the wear of tires into account in order to increase their safe duration of use. The recent progress of numerical and experimental tools can lead to a better understanding of the hydroplaning phenomenon, including the possibility of studying the behavior of worn tires on wet roads. By coupling Smoothed Particle Hydrodynamics (SPH) and Finite Element (FE) methods for modeling such fluid–structure interactions (Fourey et al., 2017; Hermange et al., 2019; Hermange et al., 2019), the present study extends our understanding of the various mechanisms involved in hydroplaning and is thus a first step in that direction. The study revolves around systematic comparisons between brand new and worn tires, analyzing local effects in order to better understand global behavior through comparisons of numerical and experimental results. To simplify this initial exploration of the physical effects involved, only a smooth ground is considered.

A Realistic Full-Scale 3D Modeling of Turning Using Coupled Smoothed Particle Hydrodynamics and Finite Element Method for Predicting Cutting Forces

Computational modelling is an effective technique for understanding the complex physics of machining. Large deformations, material separation, and high computational requirements are the key challenges faced while simulating machining. This work introduces a full-scale three-dimensional model of turning operations using a combined approach based on the Smoothed Particle Hydrodynamics (SPH) and Finite Element (FE) methods. By exploiting the advantages of each method, this approach leads to high-fidelity coupled SPH-FE machining models. Cutting forces and chip morphology are the primary results of interest. The machining models are validated with the results of turning experiments. Two-dimensional machining model underpredicts the cutting force and feed force by approximately 49% and 70%, respectively. Moreover, passive force cannot be predicted using the two-dimensional model. On the other hand, with the three-dimensional models developed in this manuscript, the difference between the total simulated force and experimentally measured force is ∼17%. The chip morphologies correlate with experiments in terms of the direction of the chip movement and the “long” continuous chips observed while turning Al 6061. This work expands the realm of machining simulations from two-dimensional orthogonal machining or sectional three-dimensional model to a full-scale realistic simulation. The encouraging simulation results show the potential to study more complex phenomena, such as machining stability and tool path modulation.

Numerical investigation on the hydrodynamic behavior of a floating breakwater with moon pool through a coupling SPH model

The moon pool opened in a floating structure significantly affects its wave attenuating performance. In this paper, the hydrodynamic behaviors of several floating breakwaters with moon pool were investigated preliminarily by the Smoothed Particle Hydrodynamics (SPH) method. For a comparative study, wave interactions with a rectangular floating breakwater and a cylindrical dual pontoon floating breakwater were also simulated. The wave was generated with a relaxation zone method which had displayed its accuracy as well as applicability. In addition, the lumped mass method was adopted to provide mooring forces for the floating breakwater. The coupling SPH model was validated by a physical model test and the numerical results were in good agreement with the experimental data. After that, the wave coefficients, such as transmitted wave coefficient, reflected wave coefficient and dissipated wave coefficient, were computed to evaluate the wave attenuating performance of floating body models. Meanwhile, for each model, the motion responses, including sway, heave and pitch, were analyzed to investigate their hydrodynamic performance. The numerical results and analysis are useful for the design of floating breakwaters, and the conclusions could be further applied in the design of wave energy converters.

Realistic computer modelling of stent retriever thrombectomy: a hybrid finite-element analysis-smoothed particle hydrodynamics model.

Stent retriever thrombectomy is a pre-eminent treatment modality for large vessel ischaemic stroke. Simulation of thrombectomy could help understand stent and clot mechanics in failed cases and provide a digital testbed for the development of new, safer devices. Here, we present a novel, in silico thrombectomy method using a hybrid finite-element analysis (FEA) and smoothed particle hydrodynamics (SPH). Inspired by its biological structure and components, the blood clot was modelled with the hybrid FEA-SPH method. The Solitaire self-expanding stent was parametrically reconstructed from micro-CT imaging and was modelled as three-dimensional finite beam elements. Our simulation encompassed all steps of mechanical thrombectomy, including stent packaging, delivery and self-expansion into the clot, and clot extraction. To test the feasibility of our method, we simulated clot extraction in simple straight vessels. This was compared against in vitro thrombectomies using the same stent, vessel geometry, and clot size and composition. Comparisons with benchtop tests indicated that our model was able to accurately simulate clot deflection and penetration of stent wires into the clot, the relative movement of the clot and stent during extraction, and clot fragmentation/embolus formation. In this study, we demonstrated that coupling FEA and SPH techniques could realistically model stent retriever thrombectomy.

Comparison of Coupled Eulerian–Lagrangian and Coupled Smoothed Particle Hydrodynamics–Lagrangian in Fluid–Structure Interaction Applied to Metal Cutting

Comparison of Coupled Eulerian–Lagrangian and Coupled Smoothed Particle Hydrodynamics–Lagrangian in Fluid–Structure Interaction Applied to Metal Cutting

Numerical Study of Interaction of Focused Waves with a Fixed Cylinder by a Hybrid Model Coupling SPH and QALE-FEM

It is of high importance to study the wave interaction with cylinder structures because they are the common types of installations in coastal and offshore engineering. In this paper, a 3-D hybrid model based on the smoothed particle hydrodynamics (SPH) and the Quasi Arbitrary Langangian-Eulerian Finite Element Method (QALE-FEM) is used to study the interaction of focused waves with fixed cylinder. The hybrid model has advantages in simulating the focused waves and cylinder interactions in terms of accuracy and efficiency by making use of respective advantage of the above-mentioned two methods. In this hybrid model, the SPH method is used in the near-field interaction between the focused waves and cylinder and the QALE-FEM method is adopted for the wave generation at the SPH boundaries.

Numerical study on near-field characteristics of landslide-generated impulse waves in channel reservoirs

Landslide-generated impulse waves (LGIWs) in channel reservoirs of mountainous regions exhibit essential differences to those in lacustrine reservoirs. We used a soil–water coupling smoothed particle hydrodynamics model to study the near-field characteristics of LGIWs in channel reservoirs. Results show that wave formation and propagation are strongly affected by the opposite bank. A three-dimensional first wave in the near field gradually transforms into a two-dimensional leading wave that travels along the channel in far field. We classify the channel reservoir into wide or narrow according to whether the first wave is visibly affected by the opposite bank. The relations between parameters of first wave and landslide parameters in the near field are obtained from a series of numerical computations. We also provide estimation formulae for the amplitude of a leading wave in a channel reservoir which is beyond the capability of former empirical relations in lacustrine reservoir. The leading wave can be used later as initial conditions for a wave propagation model. These findings are helpful for engineering estimates of LGIWs in channel reservoirs.

Coupling of SPH and Voronoi-cell lattice models for simulating fluid–structure interaction

In this study, a new methodology for coupling smoothed particle hydrodynamics (SPH) and the Voronoi-cell lattice model (VCLM) is proposed for simulating fluid–structure interaction (FSI). Free-surface flow of the fluid is modeled using SPH; the structural components are modeled by the VCLM, which accounts for both geometric and material nonlinear behaviors. The FSI algorithm is effective regardless of the mesh irregularity, which is validated through numerical simulations of the elastic opening of a dam gate. The simulation results are compared with other numerical and experimental results, which demonstrate the capabilities of the proposed method for FSI problems.

Study on Shock‐Induced Chemical Energy Release Behavior of Al/W/PTFE Reactive Material with Mechanical‐Thermal‐Chemical Coupling SPH Approach

AbstractReactive materials (RMs) are usually prepared from metal/non‐metal mixed powders through hot processing. RMs are widely used in warheads since they are inert under common conditions but release massive amounts of energy in chemical reactions induced by impact loading. However, the shock‐induced chemical energy release during impact has a complicated mechanism and needs to be further explored. This work investigated the shock‐induced chemical energy release behavior of the Al/W/PTFE RM. The experimental results show that the energy release efficiency of RM in direct ballistic tests increases with increasing impact velocity (v), and the extent of chemical reaction (y) can reach ∼0.8 at v=1250 m s−1. Meanwhile, we propose a new numerical simulation approach based on the LS‐DYNA software, combining the user‐defined equation of state considering the chemical reactions and the smoothed particle hydrodynamics (SPH) method. This approach can describe the ultra‐fast chemical reaction and crushing behavior of Al/W/PTFE RM during the impact process, taking into account the mechanical‐thermal‐chemical coupling effect. The relative errors of y between the numerical simulations and the experiments are below 25 %. Moreover, the simulation results also provide many details about the ultra‐fast chemical reactions. As v increases, the values of y and the maximum chemical reaction rate (dy/dtmax) also increase from 0.134 and 0.017 μs−1 at v=700 m s−1 to 0.882 and 0.181 μs−1 at v=1300 m s−1, respectively.