APR 自适应粒子加密 SPH 分裂融合 耦合守恒 加密触发判据 多分辨率 GPU 邻域搜索 验证基准

The aim of the present work is the investigation of an adaptive particle refinement (APR) approach that enables large variations in particle size even in the presence of a free surface. In the smoothed particle hydrodynamics (SPH) literature, the existing APR or similar multi-resolution techniques can be categorized into three main approaches, essentially driven by the discrete differential operators selected. When a conservative formulation is retained, either variable smoothing-length techniques or buffer regions are generally employed. By contrast, in formulations using accurate but non-conservative SPH operators, large variations of the particle size are achievable without requesting any specific treatment. However, because of the difficulties of such formulations in addressing the free surface, they have so far been restricted to internal flows. Recently, a regularized high-order diffusive (RHOD)-SPH approach has been derived in the context of single resolution. In this approach an accurate formulation is used inside the bulk of the fluid, whereas a conservative one is preferred in the free-surface region. In the present paper, the ingredients required in the RHOD-SPH approach are extended to APR. Specifically, the Riemann-based diffusive terms and particle shifting technique are generalized to deal with particles of different sizes. A particle-splitting procedure is employed to enlarge the range of applications of the approach. The formulation is validated on six different test cases, with comparisons to both single-resolution and reference results.

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An adaptive particle refinement (APR) algorithm has been developed for the smoothed particle hydrodynamics (SPH) method to augment the resolution of the region of interest to achieve high accuracy and simultaneously reduce the cost of computational resources. It is widely applied in the field of fluid-controlling problems involving large interface deformations, such as the two-phase flow and fluid–structure interaction because this algorithm can capture the interface with high accuracy. Nonetheless, existing APR algorithms widely encounter computational dispersion issues at the interface of regions of different particle resolutions. Moreover, traditional shifting algorithms applied in the APR processes also have difficulties in dealing with particles with different smooth lengths. In this work, an algorithm for fast particle generation was first developed based on the accelerated ray method, which accelerates the discretization of the flow field into particles. Then, a dynamic refinement/coarsening algorithm based on the APR algorithm is proposed to solve the computational dispersion problem that occurs at the refinement/coarsening interfaces. In addition, the shifting algorithm was improved in this work to ensure the particles are always well distributed during numerical calculations and, thus, can efficiently facilitate the adaptive particle refinement/coarsening processes. Comparative analysis indicates that the robust algorithms developed for the SPH method in this work can lead to more precise and reasonable flow fields compared with the conventional SPH adaptive methods.

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Particle refinement technique uses spatially varying particle distributions that focus fine resolution on areas of interest to improve accuracy and computational efficiency of the smooth particle hydrodynamics (SPH) method, but its stability at coarse/fine interfaces can be problematic. Aiming at this problem, this paper improved adaptive particle refinement (APR) technology by optimizing the interpolation method of the particle parameters in buffer area and correcting the kernel gradient of particles troubled with boundary truncation to eliminate the truncation error. Based on the improved APR adopted in δ-SPH, the numerical simulation of the viscous flows around the bluff bodies under different Reynolds numbers were carried out. Additionally, the wake flows and hydrodynamic coefficients of the bluff bodies were systematically analyzed, respectively. The validity of the improved model was verified by comparing with the values in experiment and related literature, respectively. The calculated hydrodynamic coefficient achieves good agreement with the experimental data and the wake flow phenomena observed in experiment are clearly captured. The method adopted in this paper is effective and reliable, and has certain reference value for the research of fluid dynamics fields.

In this study, a novel asymmetric adaptive particle refinement algorithm in smoothed particle hydrodynamics (SPH) is developed for soil cutting problems. Each candidate particle that located at the cutting blade of the structure is split into two “children” particles to minimize the oscillation of the contact force. And thus reduce the local instability. To minimize the density refinement error, a numerical method to determine the optimal smoothing lengths for “children” particles is given. To verify the accuracy of proposed algorithm, the adaptive refinement procedure are implemented into two models: one for soil cutting test on plane strain condition and the other for sample drilling test on axisymmetric condition. The observed flow pattern of the soil and contact forces are compared with laboratory experimental data available in the literature. Results indicate that the proposed asymmetric adaptive refinement algorithm could significantly avoid severe local instability and contributes to high-accuracy simulation.

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The rising dynamics of interacting bubbles are of fundamental importance in multiphase flow applications. In this study, an adaptive refinement smoothed particle hydrodynamics (AR-SPH) method is applied to investigate the collective behavior of four initially adjacent bubbles. The model is first validated by simulating a single bubble rising in a quiescent liquid, with displacement and velocity curves showing good agreement with reference data. On this basis, multi-bubble simulations are conducted to explore the role of surface tension, characterized by the Eotvos number (Eo = 10, 30, 50, 70, 90). The results indicate that, at low Eo, strong coalescence occurs and toroidal bubbles are formed; at moderate Eo, partial merging and breakup take place; while at high Eo, the bubbles remain separated. These findings highlight the capability of AR-SPH for resolving multi-bubble interactions and provide new insights into surface-tension-driven bubble group dynamics.

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In this article, we propose an improved refinement process for the simulation of incompressible low-viscosity turbulent flows using Smoothed Particle Hydrodynamics, under adaptive volume ratios of up to 1 : 1, 000, 000. We derive a discretized objective function, which allows us to generate ideal refinement patterns for any kernel function and any number of particles a priori without requiring intuitive initial user-input. We also demonstrate how this objective function can be optimized online to further improve the refinement process during simulations by utilizing a gradient descent and a modified evolutionary optimization. Our investigation reveals an inherent residual refinement error term, which we smooth out using improved and novel methods. Our improved adaptive method is able to simulate adaptive volume ratios of 1 : 1, 000, 000 and higher, even under highly turbulent flows, only being limited by memory consumption. In general, we achieve more than an order of magnitude greater adaptive volume ratios than prior work.

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Smoothed Particle Hydrodynamics (SPH) has emerged as a promising meshless computational method with applications in diverse fields. However, SPH faces significant challenges in computational efficiency and resolution adaptability. To address these limitations, this study introduces a novel SPH framework with anisotropic adaptive spatial resolution (AASR), which combines the strengths of anisotropic SPH (ASPH) and adaptive spatial resolution (ASR). The proposed method enables directionally anisotropic particle spacing for any single particle, along with gradual resolution transitions between neighboring particles, achieving grid‐like refinement flexibility while preserving the Lagrangian nature of SPH. Several auxiliary SPH techniques, including free surface detection, particle shifting technique and the renormalized density gradient, are improved to match the AASR framework. The framework is further enhanced by coupling with the Finite Particle Method (FPM), which improves numerical stability and accuracy in non‐uniform particle distributions. Numerical validations are conducted in five benchmark cases, including lid‐driven shear cavity flow, Taylor–Green vortex, solitary wave propagation, standing wave dissipation, and wave–floating–breakwater interaction. Results demonstrate that the AASR technique can maintain resolution in any critical regions while coarsening elsewhere. While notably improving computational efficiency, the new method preserves satisfactory numerical accuracy, with about a first‐order convergence rate in the benchmark. In addition, existing SPH enhancements or auxiliary techniques are compatible with the AASR framework after necessary modification. This work advances SPH applicability to large‐scale and multi‐resolution problems, establishing a meshless alternative with comparable resolution control to grid‐based methods.

Abstract The implementation of dynamic refinement in Smoothed Particle Hydrodynamics (SPH) cannot only describe the physical field more minutely but also decrease the computational cost because of the finer spatial resolution and the locally self-adaptive refinement. However, there are several challenges to realize the dynamic refinement in SPH to achieve improved performance. Based on these challenges, this paper provides a general dynamic refinement strategy, and a new refinement criterion involving two-phase materials is proposed to capture the interface more precisely in Fluid–Structure Interaction (FSI) problems. To prove the validity of the strategy, three different models for SPH simulations, including the dynamic refinement model, no refinement model and total refinement model, are designed for a case of water entry of a wedge. By measuring the energy, acceleration and surface pressure of the wedge and comparing the computational cost, the results indicate that this strategy can obtain better accuracy and efficiency, which demonstrates high potential for extension of SPH application to FSI problems. Meanwhile, the new refinement criterion is proven to be more effective than other single-phase refinement criteria.

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Abstract The recently developed FSI-SPH model (Sun et al., 2019c), by combining the multi-resolution δ + -SPH scheme and a Total Lagrangian SPH method, is further extended for more complex three-dimensional (3D) Fluid Structure Interaction (FSI) problems. The FSI-SPH model is strengthened with advanced numerical techniques, in which a combination of the Particle Shifting Technique (PST) and the Tensile Instability Control (TIC) is adopted to prevent flow voids induced by the tensile instability. The Adaptive Particle Refinement (APR) is used to refine particles in the boundary layer region and coarsen particles in the far-field to increase local accuracy but reduce overall computational cost. Moreover, the δ + -SPH and Total Lagrangian SPH solvers are coupled through a Modified Sequential Staggered (MSS) algorithm which, on one hand, ensures the numerical accuracy and stability and, on the other hand, improves the efficiency when magnitudes of time steps between the two solvers differ from each other significantly. In the numerical results, challenging 2D and 3D FSI cases are simulated to test the accuracy of the proposed FSI-SPH model. A new FSI benchmark with free-surface is proposed to highlight the advantage of this FSI-SPH model in simulating free-surface viscous flows. In addition, 3D effects in the FSI dam-breaking and sloshing cases are investigated.

The problem of cross-media water entry slamming of structures widely exists in military and engineering fields. The traditional numerical solution method based on grid discretization needs to use the VOF method to track the two-phase interface accurately. Therefore, based on the smoothed particle hydrodynamics methodology, a multiphase flow SPH numeric methodology combined with an adaptive particle refinement technique is proposed to emulate the structures’ slamming water-impact procedure. This method does not need mesh, avoids mesh distortion and reconstruction problems, and can accurately capture complex interfaces without additional interface tracking algorithms.

A three-dimensional smoothed-particle hydrodynamics (SPH) method is used to study the moving boundary problem of a swimming manta ray, focusing on Eulerian and Lagrangian coherent structures. The manta ray's boundary motion is predefined by a specific equation. The calculated hydrodynamic results and Eulerian coherent structures are compared with data from the literature. To improve computational stability and efficiency, the δ+-SPH model used in this study incorporates tensile instability control and an improved adaptive particle-refinement technique. By comparing and analyzing the Eulerian and Lagrangian coherent structures, the relationship between these vortex structures and hydrodynamic force generation is examined, revealing the jet mechanism in the manta ray's wake. The SPH method presented herein is robust and efficient for calculating biomimetic propulsion problems involving moving boundaries with large deformations, and it can accurately identify vortex structures. The approach of this study provides an effective simulation tool for investigating biomimetic propulsion problems such as bird flight and fish swimming.

This paper presents a multidimensional free‐surface detection method for Smoothed Particle Hydrodynamics (SPH) simulations aimed at highly dynamic flows. The approach combines density‐guided candidate selection with an efficient seed‐and‐expand strategy: outermost‐particle seeding is followed by breadth‐first search (BFS) refinement, while local surface normal estimated via principal component analysis (PCA) guide adaptive sector/cone scanning to improve robustness in high‐curvature and fragmented interfaces. To accelerate neighborhood queries, the method employs dimension‐dependent spatial indexing (hash grids in 2D and an octree in 3D), reducing the practical cost of neighbor search compared with exhaustive scanning. The framework is validated on benchmark cases including 2D/3D tank sloshing and a 3D dam‐break scenario. Results show improved interface identification accuracy over a standard density‐ratio baseline (e.g., 12.7% higher interfacial precision in our tests) and substantially faster neighborhood‐query performance (up to 72% reduction in the query stage), enabling reliable near–real‐time free‐surface detection for large‐scale SPH simulations.

Abstract The present work is dedicated to an accurate modeling of violent Fluid-Structure-Interaction (FSI) problems using a coupled Lagrangian particle method combining a multi-phase δ-SPH  scheme and a Total-Lagrangian-Particle (TLP) method. Advanced numerical techniques, e.g. Adaptive-Particle-Refinement (APR), have been included in the particle method for improving the local accuracy and the overall numerical efficiency. On one hand, this paper aims to demonstrate the capability of the proposed numerical method in modeling FSI flows with large density-ratios, strong fluid impacts, complex interfacial evolutions and considerable wall-boundary movements and deformations; On the other hand, the numerical results presented in this paper show the importance of considering the existence of air-phase in some complex FSI problems. The entrapped air-bubble, after the free-surface rolling and closing, plays an important role in the overall flow evolution and hence the hydrodynamic load on the structure. Although a density ratio as large as 1000 has been adopted, clear and sharp multi-phase interfaces, which undergo violent breakups and reconnections, are present in the numerical results, and more importantly, stable and smooth pressure fields are obtained. This contributes to an accurate prediction of the structural response, as validated by both the experimental data and other numerical results.

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Graphical processing unit (GPU) implementation of adaptive particle splitting and merging (APS) in the framework of smoothed particle hydrodynamics (SPH) is presented. Particle splitting and merging process are carried out based on a prescribed criterion. Multiple time stepping technology is used to reduce computational cost further. Detailed implementations on both single- and multi-GPU are discussed. A benchmark test that is a flow past fixed periodic circles is simulated to investigate the accuracy and speed of the algorithm. Comparable precision with uniformly fine simulation is achieved by APS, whereas computational demand is reduced considerably. Satisfactory speedup and acceptable scalability are obtained, demonstrating that GPU-accelerated APS is a promising tool to speed up large-scale particle-based simulations. (C) 2013 Elsevier B.V. All rights reserved.

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ABSTRACT A numerical inconsistency has emerged for multi-phase smoothed particle hydrodynamics simulations when using very high resolution, made possible by graphical processing units. In violent flows unphysical voids and phase separation occur ultimately leading to numerical instability. New Fickian-based particle shifting algorithms with a selectively activated free-surface correction are developed for air–water simulations to prevent the creation of unnatural voids and maintain numerical stability through nearly uniform distributions. Using the shifting algorithm without surface correction in the air phase is recommended, with marginal improvements if the shifting algorithm is not applied in water. However, maintaining shifting in water would avoid possible void occurrence. The improvement is demonstrated using a dry-bed dam break and a sloshing tank case. A 3D case involving the impact of the water flow on an obstacle is compared with experimental data. The multi-phase SPH scheme gives closer agreement with experiment than a single-phase simulation.

As a meshfree method, the smoothed particle hydrodynamics method (SPH) is suitable for fluid–particle–solid (FPS) interaction problems, such as abrasive water-jet (AWJ) impacting process. However, the fully resolved SPH model requires fine resolution of discrete particles and the computation is expensive. The coupled method of SPH and discrete element method (DEM) may be a more effective approach. A coupled SPH–DEM unresolved model is proposed in this study for AWJ simulation, which containing water-jet flow, metallic solid and abrasive particles. The fluid and solid phases are discretized with SPH particles, and the abrasives are described by the DEM method. The coupling between SPH and DEM is achieved based on the so-called local averaging techniques. To enforce the efficient interaction between SPH–DEM and SPH–SPH, a double-layer linked-list neighboring particle searching procedure is proposed for establishing particle-pair in each time step, resulting in diverse smoothing lengths in the domain. Four numerical cases are conducted to verify the model’s applicability including single/multiple particle sedimentation and continuous/discontinuous AWJ impact. The erosion process of plastic deformation, failure and material removal by AWJ impact is reproduced. The new coupled model has more computational efficiency. Results show that discontinuous AWJ has less erosion rate and more energy efficient than continuous AWJ. The effects of distance between adjacent water columns on crater profiles by discontinuous AWJ is also involved. This model has more efficiency to be suitable for the research of AWJ and complex fluid particle flow.

Abstract The non-conservation of total fluid volume, caused by the accumulating errors on the potential energy of the fluid, has been a serious numerical issue in a Weakly-Compressible SPH (WCSPH) simulation when transitional Particle Shifting Techniques (PSTs) are employed to prevent disordered particle distribution and the tensile instability from negative pressures. This paper is dedicated to, within the framework of WCSPH, developing an enhanced version that remedies the aforementioned deficiency of the traditional PSTs, and meanwhile improves the quality of the particle distribution in the vicinity of a free-surface region. To this end, a Corrective Cohesion Force (CCF) between a target particle and its interacting particles is introduced to provide adaptive compensation corresponding to the particle repositioning. Four classical benchmarks are implemented to validate the effectiveness and stability of the present PST. It is demonstrated that the new PST incorporating with the CCF shows satisfactory performance to improve the conservation of total fluid volume, and to obtain more uniform particle distribution in the proximity of the free-surface. In addition, the newly-developed PST also maintains the accuracy and stability inherited from the traditional versions, suggesting that it can be treated as an ideal alternative with regard to the traditional PSTs in a WCSPH simulation, especially for a long-term-duration case with violent free-surface evolutions.

Abstract The present work is dedicated to extending the strongly-compressible multiphase SPH Volume Adaptive Scheme (see [22] ) from Cartesian to cylindrical polar coordinates for addressing axisymmetric problems. By omitting the gradient in the circumferential direction, an Axisymmetric-SPH model is developed. Three-dimensional axisymmetric problems including rising bubbles, expanding or collapsing bubbles are conveniently and efficiently simulated using the proposed Axisymmetric-SPH model. Contrary to the purely three-dimensional SPH model established in Cartesian coordinates, with the axisymmetric model, sufficient particle resolutions can be easily adopted to reach converged simulations of complex problems. Axisymmetric-SPH results are validated either using experimental data or other numerical results. In the Axisymmetric-SPH model, a convenient and effective way of avoiding singularity at the axis is presented. In addition, the Volume Adaptive Scheme (VAS), originally developed for compressible flow simulations with large volume variations in Cartesian coordinates, is shown to be a crucial tool to adjust particle volumes in the Axisymmetric-SPH model for all flow cases, including both weakly-compressible and strongly-compressible flows.

Abstract In the present work, the single-phase and weakly-compressible δ-SPH  model is further extended to simulate multiphase and strongly-compressible flows. This is motivated by the fact that traditional SPH models can meet some difficulties when modeling strongly-compressible flows with large volume variations (e.g. expansion and collapse of cavitation bubbles). Due to the strong compressibility of the fluid, the energy equation should be considered in the governing equations. In that case, the pressure is solved based on both density and internal energy. To stabilize the pressure field, density and energy diffusive terms should be applied. Large variations of particle volumes in the compressible phase would result in large variations of particle spacing. Therefore, particle smoothing lengths are adjusted in time to maintain appropriate neighboring particles. To ensure good properties of accuracy and conservation when particles with different smoothing lengths interact, corrected SPH operators are utilized to discretize the governing equations. Moreover, in order to limit the particle volume variations and maintain a homogeneous volume distribution in the entire flow field, especially near the interface between different phases of different compressibility, a new volume adaptive scheme is proposed to control particle volumes. The volumes which are over-expanded or over-compressed will be split or merged with others, maintaining a small particle volume variation in the flow. Finally, the proposed SPH model is validated with several challenging benchmarks including expansion and collapse of underwater-explosion bubbles or cavitation bubbles. All the SPH results are compared with other numerical solutions with good agreements.

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Underwater explosions can generate substantial dynamic loads, leading to damage or failure of solid structures such as submarine pipelines. This process involves the interaction of high-pressure explosion products, water, and solid structures, characterized by transience, multi-phase interaction, and large deformations. In this study, a Lagrange mesh-free method called Smoothed Particle Hydrodynamics (SPH) is employed to establish a fluid-solid interaction (FSI) model for underwater contact explosions. The SPH discrete equations of governing equations of continuum media including fluid and solid are constructed as anti-symmetric forms based on the particle approximation technique and kernel gradient correction scheme. The equation of state is presented to describe the material response in strong interactions for the explosive, water, and solid, respectively. To simulate solid plasticity, the Johnson-Cook constitutive models are integrated into the SPH procedure to capture the behavior of large deformation and damage of metal structures. To address the issue of drastic changes in particle spacing caused by suddenly expanding gas, a modified particle regeneration technique (M-PRT) is proposed to refresh SPH particles in the gas domain according to the volume change rate. The first-order Moving Least Squares (MLS) approach is used to update the variables of refreshed particles, thus the linear variation of field variables is reproduced. The accuracy of the model is verified through several examples, including free-field underwater explosions, near-wall underwater explosions, and underwater contact explosions.

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Cavitation erosion is a pervasive issue in hydraulic machinery and ocean engineering, characterized by the collapse of bubbles, micro-jetting, and impact erosion, all exhibiting strong transient, microscale, and fluid–solid coupling features. Understanding these phenomena is essential for elucidating the mechanisms behind erosion and for developing strategies to prevent wear damage. Recognizing the limitations of conventional numerical methods, this study employs the smoothed particle hydrodynamics (SPH) method to develop a fluid–solid coupling model that simulates cavitation erosion at the bubble scale. The Lagrangian and mesh-free nature of SPH make it well-suited for tracking the transient processes of asymmetric bubble collapse, jet formation, and the subsequent impact on elastic–plastic materials. A comprehensive fluid–solid coupling SPH model is constructed, encompassing bubbles, surrounding liquids, and elastic–plastic materials. This model includes a compressible multiphase SPH approach for simulating the interaction between highly compressible bubbles and liquids. To address gas phase over-compression during bubble collapse, a modified particle regeneration technique (PRT) is introduced, allowing for automatic adjustment of particle resolution in the gas domain as it expands or compresses. For the solid simulation, an elasto-plastic constitutive model and a failure model are integrated into the SPH framework to describe material deformation and failure due to microjet impacts. These enhancements enable the simulation of the entire cavitation erosion process within a unified, mesh-free context. The SPH model is validated through simulating bubble collapse and jetting induced by shock waves. It is then applied to investigate the dynamics of cavitation erosion near both rigid and elastic–plastic materials, providing quantitative analysis of the erosion process. The outcomes of this research contribute significantly to our understanding of cavitation erosion mechanisms and offer a robust computational tool for predicting and mitigating erosion damage in related engineering applications.

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.

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Fuel Coolant Interaction (FCI), one of the critical phenomena in severe accident, involves a variety of physical phenomena including the interaction between coolant and fuel of high temperature. Especially, the jet break-up of a pre-mixing phase that the bulk of molten fuel breaks into the droplet is important for the accident progression. Understanding the intricate physics of jet break-up is essential to reduce the uncertainties of FCI and to mitigate severe accident. In this study, we have developed Lagrangian-based CFD code (named as SOPHIA) using Smoothed Particle Hydrodynamics (SPH) method, which has an advantage on handling the complicated interfacial behaviors, large deformation and multiphase flow. Furthermore, the SOPHIA code is parallelized on the multi-GPUs to achieve high-resolution and large-scale simulation that enhance the accuracy and practical applicability. Using the multi-GPU based SOPHIA code, this study simulates the benchmark jet breakup experiments in high resolution and three dimensions. The simulation results are compared with the experimental data both qualitatively and quantitatively. As a results, they shows a good agreement, and furthermore, three dimensional high resolution simulation is confirmed to resolve the physical features of jet breakup accurately by taking account into the multi-fluids interactions between jet-pool-air.

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Predictive–corrective incompressible smoothed particle hydrodynamics (PCISPH) is a promising variant of the particle-based fluid modeling technique smoothed particle hydrodynamics (SPH). In PCISPH, a dedication prediction–correction scheme is employed which allows for using a larger time step and thereby outperforms other SPH variants by up to one order of magnitude. However, certain characteristics of the PCISPH lead to severe synchronization problems that, thus far, prevented PCISPH from being applied to industrial scenarios where high performance computing techniques need to leveraged in order to simulate in appropriate resolution. In this work, we are for the first time, presenting a highly accelerated PCISPH implementation which employs a distributed multi-GPU architecture. To that end, dedicated optimization techniques are presented that allow to overcome the drawbacks caused by the algorithmic characteristics of PCISPH. Experimental evaluations on a standard dam break test case and an industrial water splash scenario confirm that PCISPH can be efficiently employed to model real-world scenarios involving a large number of particles.

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This paper presents an efficient mesoscale simulation of a Laser Powder Bed Fusion (LPBF) process using the Smoothed Particle Hydrodynamics (SPH) method. The efficiency lies in reducing the computational effort via spatial adaptivity, for which a dynamic particle refinement pattern with an optimized neighbor-search algorithm is used. The melt pool dynamics is modeled by resolving the thermal, mechanical, and material fields in a single laser track application. After validating the solver by two benchmark tests where analytical and experimental data are available, we simulate a single-track LPBF process by adopting SPH in multi resolutions. The LPBF simulation results show that the proposed adaptive refinement with and without an optimized neighbor-search approach saves almost 50% and 35% of the SPH calculation time, respectively. This achievement enables several opportunities for parametric studies and running high-resolution models with less computational effort.

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Cloth–liquid interaction involves coupled phenomena such as porous flow, absorption, emission, and diffusion, which are difficult to model in a stable and efficient manner in particle-based simulations. In this paper, we present a GPU-based cloth–liquid coupling framework that integrates these processes within a unified Smoothed Particle Hydrodynamics (SPH) pipeline. To improve directional robustness in porous flow near boundaries, we use a virtual-pressure formulation inspired by Darcy’s law, while absorption and emission are handled through saturation-based mass exchange and diffusion is applied as a sequential redistribution stage. For efficient neighbor search, the framework employs a Bitonic sort–based GPU hashing structure. We evaluate the proposed method using qualitative wet-cloth scenarios and quantitative analyses including frame-time measurement, sorting-cost comparison, scalability with increasing particle counts, mass conservation error, and module-wise timing breakdown. The results show that the proposed hashing scheme reduces sorting overhead compared with the baseline GPU implementation, while the full coupling pipeline maintains stable wetting behavior and bounded mass variation across the tested scenes. These results indicate that the proposed framework provides an efficient and numerically stable approach for GPU-based porous cloth–liquid simulation.

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In this work, the realization of density reinitialization with Smoothed Particle Hydrodynamics (SPH) techniques is examined. A self-adaptive density reinitialization method is proposed. Instead of using fixed step intervals for reinitialization, this method obtains oscillation of density field by introducing two variables for measuring the density variation acceleration and defining the density variation criteria; and then performs density reinitialization once oscillation exceeds the criteria which is self-adjusted according to the density field. Numerical test on two-dimension dam break illustrates that this method is able to adjust the reinitialization frequency according to density field oscillation during SPH simulation, while achieving good accuracy.