On the convergence of particle methods applied to the Euler and free surface equations

2006 ◽  
pp. 345-349
Author(s):  
A. Jami ◽  
M. Kermarec
Keyword(s):  
Free Surface ◽  
Particle Methods

scholarly journals Sloshing Simulation of Single-Phase and Two-Phase SPH using DualSPHysics

Kapal ◽  
2020 ◽  
Vol 17 (2) ◽  
pp. 50-57
Author(s):  
Andi Trimulyono ◽  
S Samuel ◽  
Muhammad Iqbal
Keyword(s):  
Free Surface ◽  
Pressure Sensors ◽  
Pressure Oscillation ◽  
Particle Method ◽  
Surface Flow ◽  
Particle Methods ◽  
Two Phase ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass

The sloshing phenomenon is one of the free surface flow that can endanger liquid cargo carriers such as ships. Sloshing is defined as the resonance of fluid inside a tank caused by external oscillation. When sloshing is close to the natural frequency of the tank it could endanger ships. Particle method has the advantages to be applied because sloshing is dealing with free surface. One of the particle methods is Smoothed Particle Hydrodynamics (SPH). In this study, compressible SPH was used as a result of the pressure oscillation, which exists because of the effect of density fluctuation as nature of weakly compressible SPH. To reduce pressure noise, a filtering method, Low Pass Filter,  was used to overcome pressure oscillation. Three pressure sensors were used in the sloshing experiment with a combination of motions and filling ratios. Only one pressure sensor located in the bottom was used to validate the numerical results. A set of SPH parameters were derived that fit for the sloshing problem. The SPH results show a good agreement with the experiment’s. The difference between SPH and experiment is under 1 % for sway, but a larger difference shows in roll. Low pass filter technique could reduce pressure noise, but comprehensive method needs to develop for general implementation.

scholarly journals A physically consistent particle method for high-viscous free-surface flow calculation

2021 ◽  
Author(s):  
Masahiro Kondo ◽  
Takahiro Fujiwara ◽  
Issei Masaie ◽  
Junichi Matsumoto
Keyword(s):  
Angular Momentum ◽  
Free Surface ◽  
Particle Method ◽  
Free Surface Flow ◽  
Momentum Conservation ◽  
Free Surface Flows ◽  
Surface Flow ◽  
Particle Methods ◽  
Surface Flows ◽  
Angular Momentum Conservation

AbstractParticle methods for high-viscous free-surface flows are of great use to capture flow behaviors which are intermediate between solid and liquid. In general, it is important for numerical methods to satisfy the fundamental laws of physics such as the conservation laws of mass and momentum and the thermodynamic laws. Especially, the angular momentum conservation is necessary to calculate rotational motion of high-viscous objects. However, most of the particle methods do not satisfy the physical laws in their spatially discretized system. The angular momentum conservation law is broken mostly because of the viscosity models, which may result in physically strange behavior when high-viscous free-surface flow is calculated. In this study, a physically consistent particle method for high-viscous free-surface flows is developed. The present method was verified, and its performance was shown with calculating flow in a rotating circular pipe, high-viscous Taylor–Couette flow, and offset collision of a high-viscous object.

scholarly journals MR-WC-MPS: A Multi-Resolution WC-MPS Method for Simulation of Free-Surface Flows

Water ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1349 ◽  
Author(s):  
Mohammad Amin Nabian ◽  
Leila Farhadi
Keyword(s):  
Free Surface ◽  
Free Surface Flows ◽  
Submarine Landslide ◽  
Particle Methods ◽  
Computational Time ◽  
Computational Domain ◽  
Surface Flows ◽  
Mps Method ◽  
Weakly Compressible ◽  
Moving Particle

A Multi-Resolution Weakly Compressible Moving-Particle Semi-Implicit (MR-WC-MPS) method is presented in this paper for simulation of free-surface flows. To reduce the computational costs, as with the multi-grid schemes used in mesh-based methods, there is also a need in particle methods to efficiently capture the characteristics of different flow regions with different levels of complexity in different spatial resolutions. The proposed MR-WC-MPS method allows the use of particles with different sizes in a computational domain, analogous to multi-resolution grid in grid-based methods. To evaluate the accuracy and efficiency of the proposed method, it is applied to the dam-break and submarine landslide tests. It is shown that the MR-WC-MPS results, while about 15% faster, are in good agreement with the conventional single-resolution MPS results and experimental results. The remarkable ability of the MR-WC-MPS method in providing robust savings in computational time for up to 60% is then shown by applying the method for simulation of extended submarine landslide test.

scholarly journals Time Domain Simulation of Lifting Bodies Acting at or Near the Free Surface With Vortex Particle Wakes

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
Rachel Gouveia ◽  
Stephanie Fitzpatrick ◽  
Amanda Costa ◽  
David Kring
Keyword(s):  
Free Surface ◽  
Time Domain ◽  
Potential Flow ◽  
Industrial Applications ◽  
Particle Methods ◽  
Computational Time ◽  
Flow Solver ◽  
Wake Patterns ◽  
Ocean Environment ◽  
Vortex Particle

Boundary element method (BEM) potential-flow solvers are regularly used in industrial applications due to their quick setup and computational time. In aerodynamics, vortex particle methods (VPM) are widely used with BEM potential-flow solvers for modeling lift. However, they are seldom applied to the ocean environment. This paper discusses the implementation of a VPM into Aegir, an existing time-domain, seakeeping, medium-fidelity, BEM potential-flow solver. The wake in the VPM is modeled using both a small dipole buffer wake sheet and vortex particles. It has been observed that this method captures both the details of complex wake patterns behind lift-producing surfaces and the expected lift force, thus improving the accuracy of the solution. Two new contributions presented in this paper include the extension of the VPM from previous source-based methods to a potential formulation and full interaction with free surface waves.

Solving 2D Fluid-Structure Interaction Problem by a Coupled Particle Method

2017 ◽  
Author(s):  
Ruosi Zha ◽  
Wei Qiu ◽  
Heather Peng
Keyword(s):  
Free Surface ◽  
Message Passing Interface ◽  
Numerical Solutions ◽  
Particle Methods ◽  
Particle Collision ◽  
Wave Impact ◽  
Time Step ◽  
Fluid Structure ◽  
Highly Nonlinear ◽  
Structural Responses

It is important to predict wave impact and structural responses of ship and offshore structures in extreme sea conditions. There are advantages to apply Lagrangian particle methods to simulate highly nonlinear breaking free surface flow and fluid-structure interactions (FSI). In this paper, an improved moving particle semi-implicit (MPS) method was developed to solve the FSI problems. At each time step, the fluid motions and the structural responses are solved. For flow computations, a modified mixed source term method and an improved free surface identification method were adopted to suppress pressure oscillations. Moreover, a particle collision model was used to enhance the numerical stability and avoid nonphysical solutions. The discretized Poisson equations for pressure were solved by a parallel version of the bi-conjugate gradient stabilized method based on the message passing interface (MPI) approach. For structural responses, solids were treated as isotropic elastic particles. Validation studies were carried out for cases of 2D dam breaking and its interaction with a rubber gate. The numerical solutions are in good agreement with experimental data and other published numerical results.

scholarly journals Application of background pressure with kinematic criterion for free surface extension to suppress non-physical voids in the finite volume particle method

2019 ◽  
Author(s):  
Nathan Quinlan ◽  
Mohsen Hassanzadeh Moghimi
Keyword(s):  
Free Surface ◽  
Finite Volume ◽  
Particle Method ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Particle Methods ◽  
Positive Pressure ◽  
Absolute Pressure ◽  
Free Surfaces ◽  
Spatial Discretisation

Lagrangian particle methods such as smoothed particle hydrodynamics (SPH) and the finite volume particle method (FVPM) can suffer from non-physical voids in the spatial discretisation, due to the inability of numerical particles to deform as continuum fluid elements can. It is known that the situation can be improved for wall-bounded flows in SPH by adding a uniform background pressure to ensure positive absolute pressure everywhere. In this article, we investigate the application of background pressure in FVPM, and show that numerical voids grow under negative pressure and collapse under positive pressure. To use this technique in free-surface flow, however, the background pressure must be applied as an atmospheric pressure at the free surface. A kinematic criterion for free surface extension (KCFSE) to differentiate physical free surfaces from new numerical voids has been developed, supplementing the inherent capability of FVPM to identify free-surface particles robustly. The novel method enables background pressure to be applied at physical free surfaces and throughout the fluid, but not in non-physical voids, facilitating the suppression of such spurious voids. The KCFSE is validated for a translating square cylinder inside a rectangular numerical domain, with and without a free surface, and liquid in an oscillating rectangular tank.

MPS–FEM PARTITIONED COUPLING APPROACH FOR FLUID–STRUCTURE INTERACTION WITH FREE SURFACE FLOW

2014 ◽  
Vol 11 (04) ◽  
pp. 1350101 ◽  
Author(s):  
N. MITSUME ◽  
S. YOSHIMURA ◽  
K. MUROTANI ◽  
T. YAMADA
Keyword(s):  
Free Surface ◽  
Free Particle ◽  
Fluid Structure Interaction ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Particle Methods ◽  
The Finite Element Method ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Mesh Free

Fluid–structure interaction analysis involving free surface flow has been investigated using mesh-based methods or mesh-free particle methods. While mesh-based methods have several problems in dealing with the fragmentation of geometry and moving interfaces and with the instability of nonlinear advective terms, mesh-free particle methods can deal with free surface and moving boundary relatively easily. In structural analyses, the finite element method, which is a mesh-based method, has been investigated extensively and can accurately deal with not only elastic problems but also plastic and fracture problems. Thus, the present study proposes a partitioned coupling strategy for fluid–structure interaction problems involving free surfaces and moving boundaries that calculates the fluid domain using the moving particle simulation method and the structure domain using the finite element method. As the first step, we apply a conventional serial staggered algorithm as a weak coupling scheme. In addition, for the verification of the proposed method, the problem of a breaking dam on an elastic wall is calculated, and the results are compared with the results obtained by other methods.

scholarly journals Optimisation of Free Surface Problems Using Particle Methods

PAMM ◽  
2010 ◽  
Vol 10 (1) ◽  
pp. 703-704
Author(s):  
Jan Marburger
Keyword(s):  
Free Surface ◽  
Particle Methods

On the role of tin underlays for the prevention of thermal grooving in thin gold films

1986 ◽  
Vol 44 ◽  
pp. 732-733
Author(s):  
Jin Young Kim ◽  
R. E. Hummel ◽  
R. T. DeHoff
Keyword(s):  
Thin Film ◽  
Free Surface ◽  
Grain Boundary ◽  
Beneficial Effect ◽  
Failure Mechanism ◽  
Failure Mechanisms ◽  
Distinct Advantage ◽  
Gold Films ◽  
Gold Thin Film

Gold thin film metallizations in microelectronic circuits have a distinct advantage over those consisting of aluminum because they are less susceptible to electromigration. When electromigration is no longer the principal failure mechanism, other failure mechanisms caused by d.c. stressing might become important. In gold thin-film metallizations, grain boundary grooving is the principal failure mechanism.Previous studies have shown that grain boundary grooving in gold films can be prevented by an indium underlay between the substrate and gold. The beneficial effect of the In/Au composite film is mainly due to roughening of the surface of the gold films, redistribution of indium on the gold films and formation of In2O3 on the free surface and along the grain boundaries of the gold films during air annealing.

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