scholarly journals Atmosphere loss in planet–planet collisions

2020 ◽  
Vol 496 (2) ◽  
pp. 1166-1181
Author(s):  
Thomas R Denman ◽  
Zoe M Leinhardt ◽  
Philip J Carter ◽  
Christoph Mordasini
Keyword(s):  
Specific Energy ◽  
Transition Energy ◽  
Scaling Law ◽  
The Core ◽  
Numerical Studies ◽  
Target Mass ◽  
Sufficient Energy ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Impact Energies

ABSTRACT Many of the planets discovered by the Kepler satellite are close orbiting super-Earths or mini-Neptunes. Such objects exhibit a wide spread of densities for similar masses. One possible explanation for this density spread is giant collisions stripping planets of their atmospheres. In this paper, we present the results from a series of smoothed particle hydrodynamics (sph) simulations of head-on collisions of planets with significant atmospheres and bare projectiles without atmospheres. Collisions between planets can have sufficient energy to remove substantial fractions of the mass from the target planet. We find the fraction of mass lost splits into two regimes – at low impact energies only the outer layers are ejected corresponding to atmosphere dominated loss, at higher energies material deeper in the potential is excavated resulting in significant core and mantle loss. Mass removal is less efficient in the atmosphere loss dominated regime compared to the core and mantle loss regime, due to the higher compressibility of atmosphere relative to core and mantle. We find roughly 20 per cent atmosphere remains at the transition between the two regimes. We find that the specific energy of this transition scales linearly with the ratio of projectile to target mass for all projectile-target mass ratios measured. The fraction of atmosphere lost is well approximated by a quadratic in terms of the ratio of specific energy and transition energy. We provide algorithms for the incorporation of our scaling law into future numerical studies.

scholarly journals Application of Smoothed Particle Hydrodynamics to Structural Cable Analysis

2020 ◽  
Vol 10 (24) ◽  
pp. 8983
Author(s):  
A. Ersin Dinçer ◽  
Abdullah Demir
Keyword(s):  
Numerical Model ◽  
Smoothed Particle Hydrodynamics ◽  
Solid Mechanics ◽  
Numerical Studies ◽  
Mesh Free ◽  
Longitudinal Stiffness ◽  
Damping Parameter ◽  
Particle Hydrodynamics ◽  
Deformable Bodies ◽  
Smoothed Particle

In this study, a numerical model is proposed for the analysis of a simply supported structural cable. Smoothed particle hydrodynamics (SPH)—a mesh-free, Lagrangian method with advantages for analysis of highly deformable bodies—is utilized to model a cable. In the proposed numerical model, it is assumed that a cable has only longitudinal stiffness in tension. Accordingly, SPH equations derived for solid mechanics are adapted for a structural cable, for the first time. Besides, a proper damping parameter is introduced to capture the behavior of the cable more realistically. In order to validate the proposed numerical model, different experimental and numerical studies available in the literature are used. In addition, novel experiments are carried out. In the experiments, different harmonic motions are applied to a uniformly loaded cable. Results show that the SPH method is an appropriate method to simulate the structural cable.

scholarly journals Study on Particle Inconsistency Problem in Smoothed Particle Hydrodynamics

2011 ◽  
Vol 94-96 ◽  
pp. 1638-1641 ◽  
Author(s):  
Gui Ming Rong ◽  
Hiroyuki Kisu
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
Particle Method ◽  
Second Derivative ◽  
Sph Method ◽  
New Approach ◽  
First Derivative ◽  
Numerical Studies ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Finite Particle

In the smoothed particle hydrodynamics (SPH) method, the particle inconsistency problem significantly influences the calculation accuracy. In the present study, we investigate primarily the influence of the particle inconsistency on the first derivative of field functions and discuss the behavior of several methods of addressing this problem. In addition, we propose a new approach by which to compensate for this problem, especially for functions having a non-zero second derivative, that is less computational demanding, as compared to the finite particle method (FPM). A series of numerical studies have been carried out to verify the performance of the new approach.

scholarly journals Numerical Modelling of Flow-Debris Interaction during Extreme Hydrodynamic Events with DualSPHysics-CHRONO

2021 ◽  
Vol 11 (8) ◽  
pp. 3618
Author(s):  
Gioele Ruffini ◽  
Riccardo Briganti ◽  
Paolo De Girolamo ◽  
Jacob Stolle ◽  
Bahman Ghiassi ◽  
...  
Keyword(s):  
Numerical Modelling ◽  
Mean Squared Error ◽  
Numerical Approach ◽  
Numerical Studies ◽  
Squared Error ◽  
Wide Range ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Smoothed Particle Hydrodynamics Method ◽  
Dam Break Flow

Floods can transport debris of a very wide range of dimensions, from cohesive sediments to large floating debris, such as trees and cars. The latter increases the risk associated with floods by, for example, obstructing the flow or damaging structures due to impact. The transport of this type of debris and their interaction with structures are often studied experimentally in the context of tsunamis and flash floods. Numerical studies on this problem are rare, therefore the present study focuses on the numerical modelling of the flow-debris interaction. This is achieved by simulating multiple laboratory experiments, available in the literature, of a single buoyant container transported by a dam-break flow in order to validate the chosen numerical approach. The numerical simulations are carried using the open source DualSPHysics model based on the smoothed particle hydrodynamics method coupled with the multi-physics engine CHRONO, which handles the container–bottom interactions. The trajectory, as well as the velocity of the centroid of the container, were tracked throughout the simulation and compared with the same quantities measured in the laboratory. The agreement between the model and the experiment results is quantitatively assessed using the normalised root mean squared error and it is shown that the model is accurate in reproducing the floating container trajectory and velocity.

scholarly journals Experimental and Numerical Investigations of In Situ Alloying during Powder Bed Fusion of Metals Using a Laser Beam

Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1842
Author(s):  
Andreas Wimmer ◽  
Baturay Yalvac ◽  
Christopher Zoeller ◽  
Fabian Hofstaetter ◽  
Stefan Adami ◽  
...  
Keyword(s):  
Laser Beam ◽  
Powder Bed Fusion ◽  
Stainless Steel 316L ◽  
Powder Bed ◽  
Industrial Sectors ◽  
Numerical Studies ◽  
Future Success ◽  
Particle Hydrodynamics ◽  
Smoothed Particle

Powder Bed Fusion of Metals using a Laser Beam (PBF-LB/M) is increasingly utilized for the fabrication of complex parts in various industrial sectors. Enabling a robust and reproducible manufacturing process is one of the main goals in view of the future success of PBF-LB/M. To meet these challenges, alloys that are specifically adapted to the process are required. This paper demonstrates the successful interplay of simulation studies with experimental data to analyze the basic phenomena of in situ alloying. The meshless Smoothed-Particle Hydrodynamics (SPH) method was employed for the numerical simulation of two-component powder systems considering both thermodynamics and fluid mechanics in the solid and the melt phase. The simulation results for the in situ alloying of stainless steel 316L blended with the aluminum alloy AlSi10Mg were enriched and validated with the data from a novel experimental test bench. The combination of both approaches can enhance the understanding of the process for in situ alloying. Therefore, future investigations of the PBF-LB/M process with multi-component powder systems can benefit from detailed numerical studies using SPH.

Validation DualSPHysics Code for Liquid Sloshing Phenomena

2014 ◽  
Author(s):  
Sergei K. Buruchenko ◽  
Alejandro J. C. Crespo
Keyword(s):  
Nuclear Power ◽  
Liquid Sloshing ◽  
Accident Analysis ◽  
The Core ◽  
Particle Hydrodynamics ◽  
In Series ◽  
Core Meltdown ◽  
Smoothed Particle ◽  
Smoothed Particle Hydrodynamics Method ◽  
Good Agreement

The DualSPHysics code is proposed as a numerical tool for the simulation of liquid sloshing phenomena. A particular type of sloshing motion can occur during the core meltdown of a liquid metal cooled reactor (LMR) and can lead to a compaction of the fuel in the center of the core possibly resulting in energetic nuclear power excursions. This phenomenon was studied in series of “centralized sloshing” experiments with a central water column collapsing inside the surrounding cylindrical tank. These experiments provide data for a benchmark exercise for accident analysis codes. To simulate “centralized sloshing” phenomena, a numerical method should be capable to predict the motion of the free surface of a liquid, wave propagation and reflection from the walls. The DualSPHysics code based on the smoothed particle hydrodynamics method was applied to the simulation of “centralized sloshing” experiments. Simulation results are compared with the experimental results. In a series of numerical calculations it is shown that overall motion of the liquid is in a good agreement with experimental observations. Dependence on the initial and geometrical symmetry is studied and compared with experimental data.

NUMERICAL STUDIES ON THE EXPLOSIVE WELDING BY SMOOTHED PARTICLE HYDRODYNAMICS (SPH)

2008 ◽  
Author(s):  
Katsumi Tanaka ◽  
Mark Elert ◽  
Michael D. Furnish ◽  
Ricky Chau ◽  
Neil Holmes ◽  
...  
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
Explosive Welding ◽  
Numerical Studies ◽  
Particle Hydrodynamics ◽  
Smoothed Particle

scholarly journals Phantom: A Smoothed Particle Hydrodynamics and Magnetohydrodynamics Code for Astrophysics

2018 ◽  
Vol 35 ◽  
Author(s):  
Daniel J. Price ◽  
James Wurster ◽  
Terrence S. Tricco ◽  
Chris Nixon ◽  
Stéven Toupin ◽  
...  
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
High Energy ◽  
Three Dimensions ◽  
High Energy Astrophysics ◽  
The Core ◽  
Particle Hydrodynamics ◽  
Galactic Potentials ◽  
Smoothed Particle ◽  
External Forces ◽  
Self Gravity

AbstractWe present Phantom, a fast, parallel, modular, and low-memory smoothed particle hydrodynamics and magnetohydrodynamics code developed over the last decade for astrophysical applications in three dimensions. The code has been developed with a focus on stellar, galactic, planetary, and high energy astrophysics, and has already been used widely for studies of accretion discs and turbulence, from the birth of planets to how black holes accrete. Here we describe and test the core algorithms as well as modules for magnetohydrodynamics, self-gravity, sink particles, dust–gas mixtures, H2 chemistry, physical viscosity, external forces including numerous galactic potentials, Lense–Thirring precession, Poynting–Robertson drag, and stochastic turbulent driving. Phantom is hereby made publicly available.

scholarly journals Smoothed particle hydrodynamics simulations of the core-degenerate scenario for Type Ia supernovae

2015 ◽  
Vol 450 (3) ◽  
pp. 2948-2962 ◽  
Author(s):  
G. Aznar-Siguán ◽  
E. García-Berro ◽  
P. Lorén-Aguilar ◽  
N. Soker ◽  
A. Kashi
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
Type Ia Supernovae ◽  
The Core ◽  
Type Ia ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Ia Supernovae

Analysis of Central Sloshing Experiment Using Smoothed Particle Hydrodynamics (SPH) Method

2010 ◽  
Author(s):  
Alexander Vorobyev ◽  
Vladimir Kriventsev ◽  
Werner Maschek
Keyword(s):  
Free Surface ◽  
Numerical Method ◽  
Smoothed Particle Hydrodynamics ◽  
Nuclear Power ◽  
The Core ◽  
Particle Hydrodynamics ◽  
In Series ◽  
Core Meltdown ◽  
Smoothed Particle ◽  
Sloshing Phenomenon

Liquid sloshing phenomenon is encountered whenever a liquid in a container has an unrestrained surface and can be excited. Specific type of sloshing motion can occur during the core meltdown of a liquid metal reactor (LMR) and can lead to a compaction of the fuel in the center of the core and to energetic nuclear power excursions. This phenomenon was studied in series of “centralized sloshing” experiments with a central water column collapsing inside the surrounding cylindrical tank. These experiments provide data for a benchmark exercise for accident analysis codes. To simulate “centralized sloshing” phenomenon a numerical method should be capable to predict motion of free surface of liquid, wave propagation and reflection from the walls. A meshless method based on Smoothed Particle Hydrodynamics (SPH) for the simulation of 3D free surface liquid motion has been developed. Proposed method is applied to the simulation of “centralized sloshing” experiments. Simulation results are compared with the experimental results as well as with results of computations performed with 3D code SIMMER-IV which is an advanced reactor safety analysis code that implements the traditional mesh-based numerical method. In series of numerical calculations it is shown that overall motion of the liquid is in a good agreement with experimental observations. Dependence on the initial and geometrical symmetry is studied and compared with experimental data.

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