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Abstract In this paper, we develop an optimal particle setup method for initial condition with Centroidal Voronoi Particle (CVP) dynamics, which combines the Centroidal Voronoi Tessellation (CVT) and Voronoi Particle (VP) concept. CVT optimizes the energy function in terms of compactness and consequently ensures the isotropy of particle distribution. The CVT configuration is computed by Lloyd's algorithm, which decreases the energy function monotonically. A physics-motivated model equation with tailored equation of state (EOS) is employed to relax the Voronoi particle system such that the convergent equilibrium matches the target configuration. The resulting particle distribution approximates the given analytical profiles of spatially adaptive density, smoothing-length and mass distribution with high interpolation accuracy. The level-set method is introduced to describe arbitrarily complex geometries. A set of Smoothed Particle Hydrodynamics (SPH) simulations is computed to demonstrate the performances of the proposed method. Without parameter tuning, good performance is obtained for presented benchmarks implying its promising potential. [ABSTRACT FROM AUTHOR]

In this paper, AQUAgpusph, a new free Smoothed Particle Hydrodynamics (SPH) software accelerated with OpenCL, is described. The main differences and progress with respect to other existing alternatives are considered. These are the use of the Open Computing Language (OpenCL) framework instead of the Compute Unified Device Architecture (CUDA), the implementation of the most popular boundary conditions, the easy customization of the code to different problems, the extensibility with regard to Python scripts, and the runtime output which allows the tracking of simulations in real time, or a higher frequency in saving some results without a significant performance lost. These modifications are shown to improve the solver speed, the results quality, and allow for a wider areas of application. AQUAgpusph has been designed trying to provide researchers and engineers with a valuable tool to test and apply the SPH method. Three practical applications are discussed in detail. The evolution of a dam break is used to quantify and compare the computational performance and modeling accuracy with the most popular SPH Graphics Processing Unit (GPU) accelerated alternatives. The dynamics of a coupled system, a Tuned Liquid Damper (TLD), is discussed in order to show the integration capabilities of the solver with external dynamics. Finally, the sloshing flow inside a nuclear reactor is simulated in order to show the capabilities of the solver to treat 3-D problems with complex geometries and of industrial interest. Program summary Program title: AQUAgpusph 1.5 Catalogue identifier: AEVG_v1_0 Program summary URL: http://cpc.cs.qub.ac.uk/summaries/AEVG_v1_0.html Program obtainable from: CPC Program Library, Queen’s University, Belfast, N. Ireland Licensing provisions: GNU General Public License, version 3 No. of lines in distributed program, including test data, etc.: 1702666 No. of bytes in distributed program, including test data, etc.: 75117178 Distribution format: tar.gz Programming language: C++, OpenCL, Python. Computer: Linux based computers with OpenCL support. Operating system: Linux. Has the code been vectorized or parallelized?: Code is parallelized with OpenCL. Classification: 1.5. Nature of problem: Complex geometry or heavily fragmented free surface fluid dynamics problems where mesh based method cannot be successfully applied. Solution method: SPH is a meshless method where the fluid domain is discretized as a set of fluid particles. The fields in the fluid domain are smoothed using a kernel function, that allows to develop differential operators from the flow field values in scattered sets of particles. Running time: Using an AMD HD-7970 graphic device 2×10 5 time steps of a 2-D simulation, with 10 5 particles and 8×10 2 neighs per particle, is requiring around 9 h of computation. A more detailed performance analysis will be carried out in the practical application section herein. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents a new contact algorithm to analyze an elasto-plastic contact problem using the SPH (Smoothed Particle Hydrodynamics) method. This algorithm is available to both contact types, which are the particle-to-particle contact and the surface-to-particle one. It is employed to determine the actual boundary normal vector and apply the reproducing condition in the cylindrical coordinate. The variational equation based on the virtual work principle is derived and its solution is obtained by the penalty method, which includes both a penetration and a penetration rate. Numerical simulations are presented to show that the proposed algorithm can be applied to the elasto-plastic contact problem for the case that either both bodies are deformable or one is a rigid wall and the other is deformable. Two colliding bodies can be separated with the expected rebound velocity and the total contact force acting on between them similar to theoretical value. Results of the rod impact analysis are shown to be in agreement with the ones obtained by other solution and experiment. [Copyright &y& Elsevier]