Smoothed Particle Hydrodynamics Research Articles

A Physics-Based Simulation of Fluid–Solid Coupling Scenarios in an Ocean Visual System

In the domain of ocean engineering, the authenticity of visual systems is a major challenge in developing marine simulators. A simulation strategy based on the smoothed particle hydrodynamics (SPH) simulation method is proposed in this study to enhance the realism of fluid–solid coupling scenes in a marine simulator visual system. Based on the SPH method, the water particles are constrained in each iteration according to the two physical fields of velocity divergence and density by setting an intermediate velocity. In the simulation of the fluid–structure interaction scenario, the contribution of the volume of the rigid model to the water particles is represented by a spatial map and then incorporated into the calculation of the pressure from the water particles according to the positional relationship between the water particles and the boundary. This strategy can effectively ensure the realism of the interaction between the rigid body and the waves on the one hand and significantly improve the speed of the marine simulator visual system on the other. The experiments show that this strategy can effectively save a significant amount of time and provide theoretical and technical references for enhancing the realism of a marine simulator visual system.

Smoothed Particle Hydrodynamics for free-surface and multiphase flows: a review.

The Smoothed Particle Hydrodynamics (SPH) method is expanding and applied to more and more fields, particularly in engineering. The majority of current SPH developments deal with free-surface and multiphase flows, especially for situations where geometrically complex interface configurations are involved. The present review article covers the last 25 years of development of the method to simulate such flows, discussing the related specific features of the method. A path is drawn to link the milestone articles on the topic, and the main related theoretical and numerical issues are investigated.
In particular, several SPH schemes have been derived over the years, based on different assumptions. The main ones are presented and discussed in this review underlining the different contexts and the ways in which they were derived, resulting in similarities and differences. In addition, a summary is provided of the recent corrections proposed to increase the accuracy, stability and robustness of the SPH schemes in the context of free-surface and multiphase flows, and future perspectives of development are identified placing the method within the panorama of Computational Fluid Dynamics.

Turbulent Flow Through Sluice Gate and Weir Using Smoothed Particle Hydrodynamics: Evaluation of Turbulence Models, Boundary Conditions, and 3D Effects

Understanding flow dynamics around hydraulic structures is essential for optimizing water management systems and predicting flow behavior in real-world applications. In this study, we simulate a 3D flow control system featuring a sluice gate and a weir, commonly used in hydraulic engineering. The focus is on accurately incorporating modified dynamic boundary conditions (mDBCs) and viscosity treatment to improve the simulation of complex, turbulent flows. We assess the performance of the Smoothed Particle Hydrodynamics (SPH) method in handling these challenging conditions. Especially when the boundary conditions and applicability to industry are two of the SPH method’s grand challenges. Simulations were conducted on a Graphics Processing Unit (GPU) using the DualSPHysics code. The results were compared to theoretical predictions and experimental data found in the literature. Key hydraulic characteristics, including 3D flow effects, hydraulic jump formation, and turbulent behavior, are examined. The combination of mDBCs with the Laminar plus sub-particle scale turbulence model achieved the correct simulation results. The findings demonstrate agreement between simulations, theoretical predictions, and experimental results. This work provides a reliable framework for analyzing turbulent flows in hydraulic structures and can be used as reference data or a prototype for larger-scale simulations in both research and engineering design, particularly in contexts requiring robust and precise flow control and/or environmental management.

Efficient Method for Improving Fully Implicit Scheme in Smoothed Particle Hydrodynamics for Highly Viscous and Non‐Newtonian Polymer Flow

ABSTRACTSmoothed particle hydrodynamics (SPH), a fully Lagrangian particle method, has been widely used in various applications, such as the simulation of incompressible flow with a free surface. For highly viscous flow, which typically appears in polymer processing, a fully implicit scheme, which implicitly treats both the predictor and corrector procedures of the projection method in the SPH framework, is efficient and numerically stable. This study proposes a simple and efficient fully implicit scheme that improves predictive accuracy for highly viscous flow. The proposed scheme utilizes a recently developed scheme for highly viscous flow that performs the pressure calculation before the viscosity diffusion calculation, unlike the conventional projection method. This study further improves the viscosity diffusion calculation by considering a viscous diffusion term that is usually ignored due to the continuity equation. Including this term enables us to correctly perform calculations for non‐Newtonian flows. The increase in the computational cost that results from the inclusion of the term is alleviated by introducing a two‐step method for calculating the viscous diffusion terms. The developed scheme is applied to injection molding of a polymer melt between two parallel plates. The results show that the proposed two‐step implicit scheme reproduces the fountain flow behavior near the advancing front. In addition, a three‐dimensional molding simulation of a plate with a hole shows a significant improvement in the prediction of the filling pattern in the mold.

SPH-FE coupling for the simulation of confined flow through permeable deformable membranes

AbstractWe present an extension of smoothed particle hydrodynamics (SPH) toward fluid flows involving the interaction with permeable deformable membranes. For this purpose, a coupled SPH-FE method based on a variational formulation of the immersed boundary (IB) method is developed. In the proposed method, weakly compressible SPH is used for the discretization of the fluid and a finite element (FE) method for thin structures for the discretization of the membrane. We consider confined flow in a two-dimensional fluid domain, with the membrane being represented as an elastic beam. Adopting the framework available for the IB method, the flux through the permeable membrane as described by Darcy’s law is considered. Finally, the proposed SPH-FE method is applied to two benchmark problems, i.e., the contraction of a circular membrane and the deformation of a membrane in a channel flow, comparing the numerical results with available analytical solutions.

Assessing quality and distribution of surface runoff and soil from a mixed-use catchment, Teluk Intan in Malaysia

Surface water quality of river channels has been well examined over the years, without much focus on one of the potential contributors, that is surface runoff transporting contaminants from surrounding land. By analysing the amount of contaminants present in surface runoff and soil on the ground, the potential extent of contamination can be examined in addition to the influence of different land use. The quality of surface runoff and soil from a mixed-use catchment in Teluk Intan, Malaysia was investigated for one storm event in 2023. A total of 10 points along a main road were sampled for surface runoff and soil, both of which were analysed for Total Kjeldahl Nitrogen (TKN) and lead (Pb). Both parameters concluded a higher concentration in soil compared to runoff, indicating transport across different medias. TKN was measured at a maximum of 0.0911% in runoff and 0.473% in soil. The highest Pb concentrations of 0.423 mg/L for runoff and 66.48 mg/kg for soil were recorded at the points near the Perak River bend, which is in line with Smoothed Particle Hydrodynamics (SPH) simulation results. According to the National Water Quality Standard (NWQS), the Pb concentration in runoff was beyond the Class III limit. Herein, surface runoff exhibits a significant role in contaminant transport along the observed main road and poses a risk of entry into the Perak River. The present analysis may benefit as an estimation or comparison of typical runoff pollutant loading to improve the environmental quality of similarly mixed urban-agricultural catchment in Malaysia.

Landslide-induced impacts on downstream vessels based on an accurate and robust smoothed particle hydrodynamics framework

Landslide-induced tsunami waves pose significant risks to vessels navigating or anchored in affected water bodies. To address this issue, a validated smoothed particle hydrodynamics (SPH) framework coupled with Delta-SPH method and Shifting Algorithm was assessed and then employed to investigate the impact of such waves on vessels, considering key influential factors such as landslide thickness, length, initial position, initial water depth, vessel width, and slope-to-vessel distance. The results indicate that the heave and sway motions of the vessel are primarily influenced by the initial wave, while the roll motion is mainly affected by the secondary waves. Among the parameters examined, the landslide thickness, slope-to-vessel distance, and initial water depth have the most significant effects on the maximum heave, sway, and roll values, with relative differences of 125.5%, 177.4%, and 223.0%, respectively. Variations in initial water depth led to different landslide motion patterns: the riverbed movement pattern and the chute movement pattern, which predominantly govern the generation process of secondary waves. Additionally, prediction equations for the maximum heave, sway, and roll motions of were proposed to quantitatively assess the impacts of various initial factors on vessel motion characteristics. The prediction equations reveal that the heave motion is predominantly affected by the landslide volume, the sway motion is predominantly affected by the slope-to-vessel distance, and the roll motion is primarily governed by the landslide length and initial water depth. The research provides insight into the dynamic responses of vessels under landslide-induced tsunami waves, offering valuable guidance for disaster prevention and mitigation efforts.

Volume-conserved wavy interface boundary for δ-SPH-based numerical wave flume

ABSTRACT This paper presents the first successful application of Wavy Interface (WI) free-surface wave-generation boundary model within a worldwide explicit-type Smoothed Particle Hydrodynamics (SPH) framework, namely δ-SPH. The WI model was originally designed for projection-based semi-implicit particle method, which enables wave generation using only wave height data as input, rather than any other data (e.g. velocity). Despite its innovative concept, the WI model has not been applied to any explicit SPH models, including δ-SPH, primarily due to the issue related to volume conservation error. In contrast to projection-based semi-implicit particle method, the δ-SPH has no explicit restriction on kernel summation-based density to remain constant. This feature is not suitable with WI model, which generates waves through particle generation/removal around free surface without consideration of volume conservations. In this study, to remedy this challenge and develop volume-conserving WI model, the recently proposed enhanced schemes, including corrected pressure gradient (δ-SPHC) and Volume Conservation Shifting (VCS), are incorporated fGor minimization of both local and total volume errors arising during WI wave generations. Verifications and validations are made through benchmark tests of wave propagation, wave overtopping, and solitary wave generation. The obtained results demonstrate that the presented δ-SPHC-VCS with WI model can accurately reproduce target propagating waves with local/total volumes being conserved.

Numerical simulation of landslide-generated waves based on multiphase smoothed particle hydrodynamics method with a case study of Wangjiashan landslide

Numerical simulation of landslide-generated waves based on multiphase smoothed particle hydrodynamics method with a case study of Wangjiashan landslide

Experimental and numerical study on fusion zone in the laser welding process of AA6061-T6 overlap joint: using smoothed particle hydrodynamics (SPH)

Experimental and numerical study on fusion zone in the laser welding process of AA6061-T6 overlap joint: using smoothed particle hydrodynamics (SPH)

An Improved Single‐Layer Smoothed Particle Hydrodynamics Model for Water–Soil Two‐Phase Flow

ABSTRACTIn coastal and offshore engineering, the intense water–soil motion poses significant challenges to the safety of buildings and structures. The smoothed particle hydrodynamics (SPH) method, as a mesh‐free Lagrangian solver, has considerable advantages in the numerical resolution of such problems. SPH models for the water–soil two‐phase flow can be categorized into the multilayer type and the single‐layer type. Although the single‐layer model envisions a simpler algorithm and higher computational efficiency, its accuracy, stability, and recovery of interfacial details are far from satisfactory. In the present work, an improved single‐layer model is established to alleviate these limitations. First, the soakage function, which takes effect near the phase interface, is introduced to characterize the two‐phase coupling status. Additionally, the stress diffusion term and a modified density diffusion term applicable in density discontinuity scenario are introduced to ease the numerical oscillation. Finally, to remove the unphysical voids in the interfacial region, the particle shifting technique with special treatment tailored for free‐surface particles is implemented. Validations of the proposed model are carried out by a number of numerical tests, including the erodible dam‐break problem, the wall‐jet scouring, the flushing case, and the water jet excavation. Appealing agreements with either experimental data or published numerical results have been achieved, which verifies the accuracy, stability, and robustness of the proposed model for water–soil two‐phase flows.

How Will Concrete Piles for Offshore Wind Power Be Damaged Under Seawater Erosion? Insights from a Chemical-Damage Coupling Meshless Method.

Based on the background of the continuously rising global demand for clean energy, offshore wind power, as an important form of renewable energy utilization, is booming. However, the pile foundations of offshore wind turbines are subject to long-term erosion in the harsh marine environment, and the problem of corrosion damage is prominent, which seriously threatens the safe and stable operation of the wind power system. In view of this, a meshless numerical simulation method based on smoothed particle hydrodynamics (SPH) and a method for generating the concrete meso-structures are developed. Concrete pile foundation models with different aggregate contents, particle sizes, and ion concentration diffusion coefficients are established to simulate the corrosion damage processes under various conditions. The rationality of the numerical algorithm is verified by a typical example. The results show that the increase in the aggregate percentage gradually reduces the diffusion rate of chemical ions, and the early damage development also slows down. However, as time goes, the damage will still accumulate continuously; when the aggregate particle size increases, the ion diffusion becomes more difficult, the damage initiation is delayed, and the early damage is concentrated around the large aggregates. The increase in the ion diffusion coefficient significantly accelerates the ion diffusion process, promotes the earlier and faster development of damage, and significantly deepens the damage degree. The research results contribute to a deeper understanding of the corrosion damage mechanisms of pile foundations and providing important theoretical support for optimizing the durability design of pile foundations. It is of great significance for ensuring the safe operation of offshore wind power facilities, prolonging the service life, reducing maintenance costs, and promoting the sustainable development of offshore wind power.

Development of a computational model to assess wave overtopping performance of floating structures using smoothed particle hydrodynamics

Development of a computational model to assess wave overtopping performance of floating structures using smoothed particle hydrodynamics

Sloshing analysis of an isothermal fluid in a cylindrical tank for cryogenic tank design using smoothed particle hydrodynamics

Sloshing analysis of an isothermal fluid in a cylindrical tank for cryogenic tank design using smoothed particle hydrodynamics

Towards the estimation of wall shear stress in smoothed particle hydrodynamics

AbstractOver the past few decades, smoothed particle hydrodynamics (SPH) has emerged as an alternative computational fluid dynamics (CFD) technique, yet the estimation of wall shear stress lacks adequate standardisation. Wall shear stress is a critical metric in numerous applications, and hence, this is the focus of this paper. The present study proposes a novel SPH-based method for estimating wall shear stress using velocity data from the fluid particles adjacent to the wall. Wall shear stress is then calculated at the wall based on the wall shear stress data of the neighbouring fluid particles. For laminar flow, wall shear stress is estimated directly from velocity gradients, while for turbulent flow, the Smagorinsky large eddy simulation (LES) model with eddy viscosity is used. The results obtained from the model are rigorously validated against experimental, simulation and analytical data, confirming its effectiveness across different flow conditions. This validation highlights the reliability of the proposed model for fluid dynamics and bio-fluid mechanics research.

PROBLEMS OF NUMERICAL MODELING OF LARGE-SCALE MANTLE CONVECTION IN THE SUBDUCTION ZONE

The article provides a review of modern models of large-scale mantle convection in the zone of a heavy cold oceanic plate (slab) subduction into the upper mantle. The formal approximation of the upper mantle for the present case is an incompressible Newtonian fluid with variable viscosity. It is assumed that the plate subduction is preceded by the stage of regime formation for thermo-gravitational convection in the mantle, which is caused by temperature and buoyancy of the lightweight hot substance. Important in this situation is the problem of quantitative formal modeling of phase transitions in the plate itself, as a result of which it becomes compacted due to thermal compression, removal of a part of lightweight mobile components of its original sediments and, consequently, overall weighting of the residual components of its material. It is also important to take into account the impact of mantle currents on the plate, which leads to its geometric distortion. Emphasis should also be placed on representing this plate/slab as an object of numerical modeling, since in the case of its representation as a thin elastic plate, adopted by Gustav Kirchhoff, the current hypotheses of normal remaining normal to the deformed middle surface of the plate and an unchanging thickness are violated.The aim of the work is to construct a large-scale 2D numerical model of mantle convection in the subduction zone, which takes into account the thermal gravity regime for the upper mantle and the plate, initiated by plate subduction, the influence thereon of mantle flows (mantle wind), and phase transitions in the plate. Based on smoothed particles hydrodynamics (SPH), there was constructed a computational scheme of the slab dynamics. To verify the model, there have been performed a number of computational experiments, the results of which are generally consistent with the seismotomographically identified structure of mantle flows in the subduction zone. Thus, the model appears to show fragmentary nature of the process of subduction being due to the interaction between the subducting plate and the part that remains on the surface, which leads to deformation of the descending plate.

Interaction of pipelines with landslides: analysis of mechanical properties at different strengths

Landslides, as a common geological hazard, pose a significant threat to critical infrastructure such as pipelines. With numerous large-scale engineering projects in China crossing active fault zones, the impact of geological hazards on the safe operation of pipelines is becoming increasingly prominent. To accurately assess the impact of landslides on pipelines, this study employs the open-source DualSPHysics code and constructs a three-dimensional numerical model of landslide impact on pipelines based on the Smoothed Particle Hydrodynamics (SPH) method. The study conducts a quantitative analysis of key factors such as sliding displacement and landslide scale, thoroughly exploring the mechanisms by which landslides affect pipelines. The results indicate that as the landslide displacement increases, the rate at which the pipeline's stress increases accelerates, and the rate of stress decrease after reaching the peak also accelerates. Additionally, when the width of the landslide mass increases, its volume correspondingly increases, leading to a significant enhancement in the impact force experienced by the pipeline. Furthermore, the study analyzes the impact of different initial distances between SPH particles on the pipeline to optimize the accuracy and computational efficiency of the simulations. This research not only provides new perspectives and approaches for assessing pipeline safety but also holds significant implications for enhancing pipeline disaster resistance and guiding design and safety assessments in geological engineering and infrastructure projects.

Numerical Simulation of a Marine Landslide in Gas Hydrate-Bearing Sediments Using L-GSM

The marine gas hydrates within seabed sediments and their subsequent extraction may cause landslides. Predicting landslides in hydrate-bearing sediments is particularly challenging due to the intricate nature of the marine environment. To address this issue, we have developed a Lagrangian gradient smoothing method (L-GSM) based on gradient smoothing techniques. This approach effectively eliminates the tensile instability inherent in the original Smoothed Particle Hydrodynamics (SPH) method used for modeling solid flow. Then, we applied the L-GSM to investigate the mechanics of hydrate-bearing sediments by integrating a constitutive equation specific to these sediments, which were modeled based on the artificial methane-hydrate-bearing sediment. The robustness and precision of the L-GSM were verified through various numerical examples. Furthermore, we modeled the landslides associated with hydrate-bearing sediments under varying hydrate saturation levels. The numerical findings revealed that hydrate saturation significantly affects the dynamics of landslide movement. These satisfactory results suggest that the L-GSM has the potential to be applied to geotechnical problems associated with hydrate-bearing sediment.

Investigating Kozai-Lidov oscillations and disc tearing in Be star discs

Abstract Recent simulations of Be stars in misaligned binary systems have revealed that misalignment between the disc and binary orbit can cause the disc to undergo Kozai-Lidov (KL) oscillations or disc-tearing. We build on our previous suite of three-dimensional smoothed particle hydrodynamics simulations of equal-mass systems by simulating eight new misaligned Be star binary systems, with mass-ratios of 0.1 and 0.5, or equal-mass systems with varying viscosity. We find the same phenomena occur as previously for mass ratios of 0.5, while the mass ratio of 0.1 does not cause KL oscillations or disc-tearing for the parameters examined. With increased viscosity in our equal-mass simulations, we show that these phenomena and other oscillations are damped out and do not occur. We also briefly compare two viscosity prescriptions and find they can produce the same qualitative disc evolution. Next, we use the radiative transfer code hdust to predict observable trends of a KL oscillation, and show how the observables oscillate in sync with disc inclination and cause large changes in the polarization position angle. Our models generate highly complex line profiles, including triple-peak profiles that are known to occur in Be stars. The mapping between the SPH simulations and these triple-peak features gives us hints as to where they originate. Finally, we construct interferometric predictions of how a gap in the disc, produced by KL oscillations or disc-tearing, perturbs the visibility versus baseline curve at multiple wavelengths, and can cause large changes to the differential phase profile across an emission line.

Simulation of continuous gas-lift technique in oil-gas systems using OpenFOAM and the Volume of Fluid method

In order to maintain optimal production rates in oil reservoirs, artificial lift methods are employed as reservoir pressure declines over time due to oil extraction. The gas lift technique is one of such methods where a compressed gas, usually a mixture of hydrocarbons with low molecular weight, is injected into the lower section of the pipeline through valves. The expected result is that the additional energy provided will propel the oil to the surface and the mixture of gas and oil will have a lower effective density, thus making it easier to be transported to the surface. This artificial lift method, when applied to restore productivity is not limited by the well depth and can be applied to offshore facilities and allows operation regimes in both continuous or intermittent lift. While computational fluid dynamics (CFD) simulations for gas lift problems commonly use commercial softwares, we propose CFD simulations using the free toolbox OpenFOAM-10 using the Volume of Fluid (VOF) method. This approach aims to simulate a gas lift scenario where a methane-like gas is injected horizontally into a pipe containing upward-flowing oil, replicating real-world oil industry conditions. The main goal is to investigate the gas lift process, analyzing how the gas propels oil and increases oil production compared to scenarios without gas lift. We focus on the continuous gas lift injection regime and compare VOF simulation results with those obtained from the Smoothed Particle Hydrodynamics (SPH) method for the same problem.