scholarly journals A Lagrangian Particle Algorithm (SPH) for an Autocatalytic Reaction Model with Multicomponent Reactants

Processes ◽  
2019 ◽  
Vol 7 (7) ◽  
pp. 421
Author(s):  
Qingzhi Hou ◽  
Jiaru Liu ◽  
Jijian Lian ◽  
Wenhuan Lu
Keyword(s):  
High Resolution ◽  
Reaction Model ◽  
Autocatalytic Reaction ◽  
Numerical Dissipation ◽  
Reacting Flow ◽  
Lagrangian Particle ◽  
Particle Hydrodynamics ◽  
High Resolution Technique ◽  
Eulerian Methods ◽  
Reaction Equations

For the numerical simulation of convection-dominated reacting flow problems governed by convection-reaction equations, grids-based Eulerian methods may cause different degrees of either numerical dissipation or unphysical oscillations. In this paper, a Lagrangian particle algorithm based on the smoothed particle hydrodynamics (SPH) method is proposed for convection-reaction equations and is applied to an autocatalytic reaction model with multicomponent reactants. Four typical Eulerian methods are also presented for comparison, including the high-resolution technique with the Superbee flux limiter, which has been considered to be the most appropriate technique for solving convection-reaction equations. Numerical results demonstrated that when comparing with traditional first- and second-order schemes and the high-resolution technique, the present Lagrangian particle algorithm has better numerical accuracy. It can correctly track the moving steep fronts without suffering from numerical diffusion and spurious oscillations.

scholarly journals A parameter-free total Lagrangian smooth particle hydrodynamics algorithm applied to problems with free surfaces

2021 ◽  
Author(s):  
Kenny W. Q. Low ◽  
Chun Hean Lee ◽  
Antonio J. Gil ◽  
Jibran Haider ◽  
Javier Bonet
Keyword(s):  
Ad Hoc ◽  
Wide Spectrum ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Point Of View ◽  
Numerical Dissipation ◽  
Lagrangian Description ◽  
Smooth Particle Hydrodynamics ◽  
Particle Hydrodynamics ◽  
Sph Algorithm

AbstractThis paper presents a new Smooth Particle Hydrodynamics computational framework for the solution of inviscid free surface flow problems. The formulation is based on the Total Lagrangian description of a system of first-order conservation laws written in terms of the linear momentum and the Jacobian of the deformation. One of the aims of this paper is to explore the use of Total Lagrangian description in the case of large deformations but without topological changes. In this case, the evaluation of spatial integrals is carried out with respect to the initial undeformed configuration, yielding an extremely efficient formulation where the need for continuous particle neighbouring search is completely circumvented. To guarantee stability from the SPH discretisation point of view, consistently derived Riemann-based numerical dissipation is suitably introduced where global numerical entropy production is demonstrated via a novel technique in terms of the time rate of the Hamiltonian of the system. Since the kernel derivatives presented in this work are fixed in the reference configuration, the non-physical clumping mechanism is completely removed. To fulfil conservation of the global angular momentum, a posteriori (least-squares) projection procedure is introduced. Finally, a wide spectrum of dedicated prototype problems is thoroughly examined. Through these tests, the SPH methodology overcomes by construction a number of persistent numerical drawbacks (e.g. hour-glassing, pressure instability, global conservation and/or completeness issues) commonly found in SPH literature, without resorting to the use of any ad-hoc user-defined artificial stabilisation parameters. Crucially, the overall SPH algorithm yields equal second order of convergence for both velocities and pressure.

scholarly journals Shock-induced star cluster formation in colliding galaxies

2010 ◽  
Vol 6 (S270) ◽  
pp. 483-486 ◽  
Author(s):  
Takayuki R. Saitoh ◽  
Hiroshi Daisaka ◽  
Eiichiro Kokubo ◽  
Junichiro Makino ◽  
Takashi Okamoto ◽  
...  
Keyword(s):  
High Resolution ◽  
Shock Compression ◽  
Smoothed Particle Hydrodynamics ◽  
Formation Process ◽  
Cluster Formation ◽  
Star Clusters ◽  
Star Cluster ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Number Of Particles

AbstractWe studied the formation process of star clusters using high-resolutionN-body/smoothed particle hydrodynamics simulations of colliding galaxies. The total number of particles is 1.2×108for our high resolution run. The gravitational softening is 5 pc and we allow gas to cool down to ~10 K. During the first encounter of the collision, a giant filament consists of cold and dense gas found between the progenitors by shock compression. A vigorous starburst took place in the filament, resulting in the formation of star clusters. The mass of these star clusters ranges from 105−8M⊙. These star clusters formed hierarchically: at first small star clusters formed, and then they merged via gravity, resulting in larger star clusters.

NanoXCT—A High-Resolution Technique For TSV Characterization

2011 ◽  
Author(s):  
Sven Niese ◽  
Peter Krueger ◽  
Ehrenfried Zschech
Keyword(s):  
High Resolution ◽  
High Resolution Technique

Creep rate spectroscopy using a laser interferometer as ultra-high resolution technique for study of relaxations

1997 ◽  
Vol 119 (1) ◽  
pp. 79-87 ◽  
Author(s):  
Nina N. Peschanskaya ◽  
Pavel N. Yakushev ◽  
Alfred B. Sinani ◽  
Vladimir A. Bershtein
Keyword(s):  
High Resolution ◽  
Creep Rate ◽  
Laser Interferometer ◽  
High Resolution Technique

scholarly journals The Kelvin–Helmholtz instability and smoothed particle hydrodynamics

2019 ◽  
Vol 488 (4) ◽  
pp. 5210-5224 ◽  
Author(s):  
Terrence S Tricco
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
Initial Conditions ◽  
Initial Density ◽  
Artificial Viscosity ◽  
Numerical Dissipation ◽  
Reference Solution ◽  
Helmholtz Instability ◽  
Non Linear ◽  
Particle Hydrodynamics ◽  
Smoothed Particle

ABSTRACT We perform simulations of the Kelvin–Helmholtz instability using smoothed particle hydrodynamics (SPH). The instability is studied both in the linear and strongly non-linear regimes. The smooth, well-posed initial conditions of Lecoanet et al. (2016) are used, along with an explicit Navier–Stokes viscosity and thermal conductivity to enforce the evolution in the non-linear regime. We demonstrate convergence to the reference solution using SPH. The evolution of the vortex structures and the degree of mixing, as measured by a passive scalar ‘colour’ field, match the reference solution. Tests with an initial density contrast produce the correct qualitative behaviour. The $\mathcal {L}_2$ error of the SPH calculations decreases as the resolution is increased. The primary source of error is numerical dissipation arising from artificial viscosity, and tests with reduced artificial viscosity have reduced $\mathcal {L}_2$ error. A high-order smoothing kernel is needed in order to resolve the initial velocity amplitude of the seeded mode and inhibit excitation of spurious modes. We find that standard SPH with an artificial viscosity has no difficulty in correctly modelling the Kelvin–Helmholtz instability and yields convergent solutions.

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