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On Validating an Astrophysical Simulation Code

A. C. Calder, B. Fryxell, T. Plewa, R. Rosner, L. J. Dursi, V. G. Weirs, T. Dupont, H. F. Robey, J. O. Kane, B. A. Remington, R. P. Drake, G. Dimonte (+6 others)
2002 Astrophysical Journal Supplement Series  
We describe verification tests regularly administered to the code, present the results of new verification tests, and outline a method for testing general equations of state.  ...  We describe methodology and discuss solutions to difficulties encountered in verification and validation.  ...  The authors thank Mike Papka and the Argonne National Laboratory for visualization support and Ed Brown, Jim Truran, and Margaret Pepperdene for previewing this manuscript.  ... 
doi:10.1086/342267 fatcat:ppg4zdn4rvfkrflhqaty4hoy7a

Verification Studies for the Noh Problem using Non-ideal Equations of State and Finite Strength Shocks [article]

Sarah C. Burnett, Kevin G. Honnell, Scott D. Ramsey, Robert L. Singleton Jr
2018 arXiv   pre-print
The exact solutions are used to perform a variety of quantitative code verification studies of the Los Alamos National Laboratory Lagrangian hydrocode FLAG.  ...  For the planar case the solution can be applied to shocks of arbitrary strength, but for cylindrical and spherical geometries it is required that the analysis be restricted to strong shocks.  ...  Acknowledgements This work was performed under the auspices of the United States Department of Energy by Los Alamos National Security, LLC, at Los Alamos National Laboratory  ... 
arXiv:1706.04629v3 fatcat:kamcuhl2ajci3nvtsd3i3v23wu

THE BIERMANN CATASTROPHE IN NUMERICAL MAGNETOHYDRODYNAMICS

Carlo Graziani, Petros Tzeferacos, Dongwook Lee, Donald Q. Lamb, Klaus Weide, Milad Fatenejad, Joshua Miller
2015 Astrophysical Journal  
Direct implementation of the Biermann effect in MHD codes does not capture this physical process, and worse, produces unphysical magnetic fields at shocks whose value does not converge with resolution.  ...  Generation of magnetic fields by the Biermann effect due to mis-aligned density and temperature gradients in smooth flow behind shocks is well known.  ...  the fluid variables fail in the presence of a discontinuity.  ... 
doi:10.1088/0004-637x/802/1/43 fatcat:q6denxzyxnet7l6bajaclsj2uq

Three-temperature plasma shock solutions with gray radiation diffusion

B. M. Johnson, R. I. Klein
2016 Shock Waves  
The effects of radiation on the structure of shocks in a fully-ionized plasma are investigated by solving the steady-state fluid equations for ions, electrons, and radiation.  ...  a straightforward and comprehensive verification test methodology for multi-physics numerical algorithms.  ...  Acknowledgements We thank Jim Ferguson, Miguel Holgado, Rob Lowrie, George Zimmerman and the referees for helpful discussions and comments.  ... 
doi:10.1007/s00193-016-0649-9 fatcat:lzusw4uwzrgknib5q6ny2lsqxy

Astrophysical Validation [article]

A. C. Calder, D. M. Townsley
2018 arXiv   pre-print
First, we present a study aimed at validating hydrodynamicswith high energy density laboratory experiments probing shocks and fluid instabilities.  ...  Simulating these events thus necessitates the development of sub-grid-scale models and the capability to post-process simulations with higher-fidelitymethods.We present an overview of the problem of validating  ...  Acknowledgements This contribution was supported in part by the Department of Energy through grant DE-FG02-87ER40317 and the research described here was supported in part by earlier grant B341495 to the  ... 
arXiv:1809.02180v1 fatcat:ymq5mrjd45hbtbz6ykeh73aeeq

A Computational Fluid Dynamic Investigation of Inhomogeneous Hydrogen Flame Acceleration and Transition to Detonation

Reza Khodadadi Azadboni, Ali Heidari, Jennifer X. Wen
2018 Flow Turbulence and Combustion  
The present numerical investigation aims to study the dynamics of Deflagration to Detonation Transition (DDT) in inhomogeneous hydrogen/air mixtures and examine the effects of obstacle blockage ratio in  ...  VCEFoam uses the Harten-Lax-van Leer-Contact (HLLC) scheme fr the convective fluxes contribution and shock capturing.  ...  Publisher's Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. Open Access  ... 
doi:10.1007/s10494-018-9977-4 pmid:30613185 pmcid:PMC6297206 fatcat:uil5qves45c5voib7vswegevhi

The verification basis of the ESPROSE.m code

T.G Theofanous, W.W Yuen, K Freeman, X Chen
1999 Nuclear Engineering and Design  
An overall verification approach for the ESPROSE.m code is presented and implemented.  ...  Each step in turn consists of an array of analytical and experimental tests.  ...  Acknowledgements This work was supported under the ROAAM program carried out for the US DOE's Advanced Reactor Severe Accident Program (ARSAP), under ANL subcontract No. 23572401 to UCSB.  ... 
doi:10.1016/s0029-5493(99)00030-8 fatcat:turmdweldjeytlw7n5kchph4ba

Feature Mining Paradigms for Scientific Data [chapter]

Ming Jiang, Tat-Sang Choy, Sameep Mehta, Matt Coatney, Steve Barr, Kaden Hazzard, David Richie, Srinivasan Parthasarathy, Raghu Machiraju, David Thompson, John Wilkins, Boyd Gatlin
2003 Proceedings of the 2003 SIAM International Conference on Data Mining  
In this paper, we present our research on a unified framework that addresses this critical challenge in two science domains: computational fluid dynamics and molecular dynamics.  ...  Our framework includes two paradigms for feature mining, and the choice of one over the other, for a given application, can be determined based on local or global influence of relevant features in the  ...  A shock is a compression wave that may occur in fluid flows when the velocity of the fluid exceeds the local speed of sound.  ... 
doi:10.1137/1.9781611972733.2 dblp:conf/sdm/JiangCMCBHRPMTWG03 fatcat:vdyzq5ceqbf5tpao65anfvqsjy

The Issue with Diffusive Shock Acceleration [article]

Damiano Caprioli, Colby C. Haggerty
2019 arXiv   pre-print
We single out which standard assumptions of test-particle and non-linear DSA are violated in the presence of strong (self-generated) magnetic turbulence and put forward a novel theory in better agreement  ...  We discuss the recent developments in the theory of diffusive shock acceleration (DSA) by using both first-principle kinetic plasma simulations and analytical theory based on the solution of the convection  ...  In the presence of strong magnetic field amplification [25] , the velocity of the CR scattering centers relative to the fluid may become non-negligible, and -provided that waves travel in the "correct  ... 
arXiv:1909.06288v1 fatcat:6etj7gsfw5dgpiretqg2uyo2xy

Computational study of shock-wave interaction with solid obstacles using immersed boundary methods

A. Chaudhuri, A. Hadjadj, O. Sadot, E. Glazer
2011 International Journal for Numerical Methods in Engineering  
The IB is a general simulation method for FSI, whereas the WENO is an efficient scheme for fluid flow simulations and shock waves, and both of them work on regular cartesian grids.  ...  The objective is to avoid excessive numerical damping of the flow features over a wide range of length scales as well as to prevent spurious numerical oscillations near shock waves and discontinuities.  ...  ACKNOWLEDGEMENTS The authors gratefully acknowledge stimulating discussions with Prof. Gabi Ben-Dor from Ben-Gurion University (Israel) during the course of this study.  ... 
doi:10.1002/nme.3271 fatcat:5iryyyaepregrhe22nr4cpkwnm

Solutions of the imploding shock problem in a medium with varying density [article]

Itamar Giron, Shmuel Balberg, Menahem Krief
2021 arXiv   pre-print
We then demonstrate how the analytic solutions can be reproduced in Lagrangian hydrodynamic codes, thus demonstrating their usefulness as a code validation and verification test problem.  ...  The self-similar solutions, and specifically the similarity exponent which determines the behavior of the accelerating shock, are studied in detail, for cylindrical and spherical symmetries and for a wide  ...  The converging nature of the flow, coupled with compression and shock discontinuity, present unique subtleties, and is therefore very useful for code validation and verification, given that the results  ... 
arXiv:2106.04971v1 fatcat:kel2335xpraennr3mkqi2bnxiq

Incorporation of Fluid Compressibility into the Calculation of the Stationary Mode of Operation of a Hydraulic Device at High Fluid Pressures

V. A. Tenenev, Kalashnikov Izhevsk State Technical University, T. Raeder, A. A. Chernova, Kalashnikov Izhevsk State Technical University, Kalashnikov Izhevsk State Technical University
2021 Nelineinaya Dinamika  
A detailed validation and verification of the developed numerical method is provided, and relevant schemes and algorithms are given.  ...  high values of pressures in the valve.  ...  fluid model and that calculated within the weakly compressible fluid model are in good agreement with each other in the axisymmetric part of the valve.  ... 
doi:10.20537/nd210205 fatcat:gadybv4t6za5vjoylqpcumqtqq

A multi-material flow solver for high speed compressible flows

Anil Kapahi, Chao-Tsung Hsiao, Georges L. Chahine
2015 Computers & Fluids  
The method has shown capability to resolve and capture non-linear waves such as shock waves, rarefaction waves, and contact discontinuities in complex geometries.  ...  This work mainly emphasizes the handling of shockwave interaction with bubbles, bubbly media, and multi-fluid interfaces in a compressible flow framework.  ...  We acknowledge gratefully the support of both organizations.  ... 
doi:10.1016/j.compfluid.2015.03.016 fatcat:3dobq74jwfdhhcuz4pg4vlurbe

Grid-converged solution and analysis of the unsteady viscous flow in a two-dimensional shock tube

Guangzhao Zhou, Kun Xu, Feng Liu
2018 Physics of Fluids  
The flow in a shock tube is extremely complex with dynamic multi-scale structures of sharp fronts, flow separation, and vortices due to the interaction of the shock wave, the contact surface, and the boundary  ...  Prediction and understanding of the complex fluid dynamics is of theoretical and practical importance.  ...  In §6 we discuss and analyse the detailed evolution of the fluid dynamics revealed by the numerical solution starting from the initiation of the incident shock wave and contact surface through a sequence  ... 
doi:10.1063/1.4998300 fatcat:v7merenhlff4fnwu2z5n7u3rxq

Dynamical Phase Transition in Neutron Stars

R. Prasad, Ritam Mallick
2018 Astrophysical Journal  
In this work, we have studied the dynamical evolution of the shock front in a neutron star.  ...  The conversion of nuclear to quark matter is assumed to take place at the shock discontinuity.  ...  On the left side of the discontinuity, the fluid is at higher pressure and density whereas on the right side the fluid is at much lower pressure and density.  ... 
doi:10.3847/1538-4357/aabf3b fatcat:2cesjmmrhnap3e6v3mejiodbay
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