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Monte Carlo Sensitivity Analyses Of Dsmc Parameters For Ionizing Hypersonic Flows
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Book Synopsis Monte Carlo Sensitivity Analyses of DSMC Parameters for Ionizing Hypersonic Flows by : Kyle J. Higdon
Download or read book Monte Carlo Sensitivity Analyses of DSMC Parameters for Ionizing Hypersonic Flows written by Kyle J. Higdon and published by . This book was released on 2018 with total page 692 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work focuses on the development and sensitivity analyses of a direct simulation Monte Carlo (DSMC) code to understand the complex physical processes that occur during hypersonic entry into a rarefied atmosphere. Simulations are performed on 1-dimensional hypersonic shock scenarios that mimic the conditions of high altitude atmospheric entry to Earth and Saturn with the Computation of Hypersonic Ionizing Particles in Shocks (CHIPS) code. To model hypersonic entry problems accurately, the CHIPS code must resolve nonequilibrium flows and account for a number of complex gas dynamics processes at the molecular level. In this thesis, several high temperature models are added to the CHIPS code including charged particle models and electronic excitation. These models are refined using preliminary sensitivity analyses resulting in improved electronic excitation models and a new backward chemical reaction model. The CHIPS simulations completed in this work reproduce rarefied hypersonic shock tube experiments performed in the Electric Arc Shock Tube (EAST) at NASA Ames Research Center. The CHIPS results are post-processed by the NEQAIR line-by-line radiative solver to compare directly to spectra measured experimentally in EAST. The DSMC techniques used to model hypersonic phenomena require numerous experimentally calibrated parameters. Many of these parameters are inferred from lower temperature experiments, resulting in an unknown amount of uncertainty in the simulated results at the extreme conditions of hypersonic flow. A global Monte Carlo sensitivity analysis is performed by simultaneously varying the CHIPS input parameter values to understand the sensitivity of experimentally measured quantities simulated by the CHIPS and NEQAIR codes. The sensitivity of several of these output quantities is used to rank the input parameters, identifying the most important parameters for the simulation of the hypersonic scenario. It was concluded that experimentally measured radiation intensity is most sensitive to the following key processes: N+e−⇌N++e−+e−, NO+N+⇌N+NO+, N2+N⇌N+N+N, N+O⇌NO++e−, N+N⇌N2++e−, and Z [subscript elec] for N, O, and N2+. In the future, this ranking can be used to identify which input parameters should be experimentally investigated, where model improvements could be beneficial, and aid in reducing the parameter space for DSMC calibrations to experimental data.
Book Synopsis DSMC Simulations of Hypersonic Flows and Comparison With Experiments by :
Download or read book DSMC Simulations of Hypersonic Flows and Comparison With Experiments written by and published by . This book was released on 2005 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper presents computational results obtained with the direct simulation Monte Carlo (DSMC) method for several biconic test cases in which shock interactions and flow separation-reattachment are key features of the flow. Recent ground-based experiments have been performed for several biconic configurations and surface heating rate and pressure measurements have been proposed for code validation studies. The present focus is to expand on the current validating activities for a relatively new DSMC code called DS2V that Bird (second author) has developed. Comparisons with experiments and other computations help clarify the agreement currently being achieved between computations and experiments and to identify the range of measurement variability of the proposed validation data when benchmarked with respect to the current computations. For the test cases with significant vibrational nonequilibrium, the effect of the vibrational energy surface accommodation on heating and other quantities is demonstrated.
Book Synopsis DSMC Simulation of Separated Flows about Flared Bodies at Hypersonic Conditions by : James N. Moss
Download or read book DSMC Simulation of Separated Flows about Flared Bodies at Hypersonic Conditions written by James N. Moss and published by . This book was released on 2000 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper describes the results of a numerical study of interacting hypersonic flows at conditions that can be produced in ground-based test facilities. The computations are made with the direct simulation Monte Carlo (DSMC) method of Bird. The focus is on Mach 10 flows about flared axisymmetric configurations, both hollow cylinder flares and double cones. The flow conditions are those for which experiments have been or will be performed in the ONERA R5Ch low-density wind tunnel and the Calspan-University of Buffalo Research Center (CUBRC) Large Energy National Shock (LENS) tunnel. The range of flow conditions, model configurations, and model sizes provides a significant range of shock/shock and shock/boundary layer interactions at low Reynolds number conditions. Results presented will highlight the sensitivity of the calculations to grid resolution, contrast the difference in flow structure for hypersonic cold flows and those of more energetic but still low enthalpy flows, and compare the present results with experimental measurements for surface heating, pressure, and extent of separation.
Book Synopsis Parallel Direct Simulation Monte Carlo (DSMC) Methods for Modeling Rarefied Reactive and Non-reactive Hypersonic Flow by :
Download or read book Parallel Direct Simulation Monte Carlo (DSMC) Methods for Modeling Rarefied Reactive and Non-reactive Hypersonic Flow written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Monte Carlo Based Uncertainty and Sensitivity Analysis for Building Performance Simulation by : Sebastian Burhenne
Download or read book Monte Carlo Based Uncertainty and Sensitivity Analysis for Building Performance Simulation written by Sebastian Burhenne and published by . This book was released on 2014-01-19 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Monte Carlo Sensitivity Analysis of Unknown Parameters in Hazardous Materials Transportation Risk Assessment by : J. J. Pet-Armacost
Download or read book Monte Carlo Sensitivity Analysis of Unknown Parameters in Hazardous Materials Transportation Risk Assessment written by J. J. Pet-Armacost and published by . This book was released on 1999 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Improved Chemistry Models for DSMC Simulations of Ionized Rarefied Hypersonic Flows by : Takashi Ozawa
Download or read book Improved Chemistry Models for DSMC Simulations of Ionized Rarefied Hypersonic Flows written by Takashi Ozawa and published by . This book was released on 2007 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Monte Carlo Simulation of Three-dimensional Hypersonic Flows on Parallel Architectures by : Robert Paul Nance
Download or read book Monte Carlo Simulation of Three-dimensional Hypersonic Flows on Parallel Architectures written by Robert Paul Nance and published by . This book was released on 1995 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Monte Carlo Simulation of Radiation in Hypersonic Flows by :
Download or read book Monte Carlo Simulation of Radiation in Hypersonic Flows written by and published by . This book was released on 2002 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: Radiation is generated in hypersonic flows of missiles. Depending on the flight altitude, the gas dynamics may be modeled by continuum or kinetic simulation techniques At high altitude, kinetic methods are more physically accurate, but continuum methods are more numerically efficient. In an attempt to utilize the best of both approaches, we are undertaking the development of a hybrid continuum-kinetic method for high altitude hypersonic flows. Ultimately, such a method will provide the ability to obtain physically accurate and numerically efficient predictions of the radiation generated by hypersonic missiles The development of this hybrid method involves two important steps: (1) determination in a flow field of when to switch between the continuum and kinetic methods (a so-called continuum breakdown parameter); and (2) smooth and physically accurate communication of data between the continuum and kinetic methods. This report describes a first version of such a hybrid code that is applied to a hypersonic flow over a two-dimensional wedge. The preliminary results are encouraging although they also point to areas where the method requires improvement.
Book Synopsis International Aerospace Abstracts by :
Download or read book International Aerospace Abstracts written by and published by . This book was released on 1999 with total page 974 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Sensitivity Analysis Using the Monte Carlo Acceptance-Rejection Method by : George S. Fishman
Download or read book Sensitivity Analysis Using the Monte Carlo Acceptance-Rejection Method written by George S. Fishman and published by . This book was released on 1988 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper describes a Monte Carlo sampling plan for estimating how a function varies in response to changes in its arguments. Most notably, the plan effects this sensitivity analysis by applying the acceptance-rejection technique to data sampled at only one specified setting for the arguments, thus saving considerable computing time when compared to alternative methods. The plan which applies for a 0-1 response on each replication has immediate application when estimating variation in system performance measures in reliability analysis. The paper derives the variances of the proposed estimators and shows how to use worst case bounds on these or on corresponding coefficients of variation to choose the arguments, at which to sample, that minimize the worst case bounds. Individual and simultaneous confidence intervals are derived and an example based on s-t reliability illustrates the method. The paper also compares the proposed method and an alternative Monte Carlo approach that uses an importance function. (KR).
Download or read book Applied mechanics reviews written by and published by . This book was released on 1948 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Scientific and Technical Aerospace Reports by :
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 728 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Hypersonic and High Temperature Gas Dynamics by : John David Anderson
Download or read book Hypersonic and High Temperature Gas Dynamics written by John David Anderson and published by AIAA. This book was released on 1989 with total page 710 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a self-contained text for those students and readers interested in learning hypersonic flow and high-temperature gas dynamics. It assumes no prior familiarity with either subject on the part of the reader. If you have never studied hypersonic and/or high-temperature gas dynamics before, and if you have never worked extensively in the area, then this book is for you. On the other hand, if you have worked and/or are working in these areas, and you want a cohesive presentation of the fundamentals, a development of important theory and techniques, a discussion of the salient results with emphasis on the physical aspects, and a presentation of modern thinking in these areas, then this book is also for you. In other words, this book is designed for two roles: 1) as an effective classroom text that can be used with ease by the instructor, and understood with ease by the student; and 2) as a viable, professional working tool for engineers, scientists, and managers who have any contact in their jobs with hypersonic and/or high-temperature flow.
Download or read book NASA SP. written by and published by . This book was released on 1993 with total page 590 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The DSMC Method written by G. A. Bird and published by . This book was released on 2013-08-19 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt: Direct Simulation Monte Carlo is a well-established method for the computer simulation of a gas flow at the molecular level. While there is a limit to the size of the flow-field with respect to the molecular mean free path, personal computers now allow solutions well into the continuum flow regime. The method can be applied to basic problems in gas dynamics and practical applications range from microelectromechanics systems (MEMS) to astrophysical flows. DSMC calculations have assisted in the design of vacuum systems, including those for semiconductor manufacture, and of many space vehicles and missions. The method was introduced by the author fifty years ago and it has been the subject of two monographs that have been published by Oxford University Press. It is now twenty years since the second of these was written and, since that time, most DSMC procedures have been superseded or significantly modified. In addition, visual interactive DSMC application programs have been developed that have proved to be readily applicable by non-specialists to a wide variety of practical problems. The computational variables are set automatically within the code and the programs report whether or not the criteria for a good calculation have been met. This book is concerned with the theory behind the current DSMC molecular models and procedures, with their integration into general purpose programs, and with the validation and demonstration of these programs. The DSMC and associated programs, including all source codes, can be freely downloaded through links that are provided in the book. The main accompanying program is simply called the "DSMC program" and, in future versions of the book, it will be applicable to homogeneous (or zero-dimensional) flows through to three-dimensional flow. All DSMC simulations are time-accurate unsteady calculations, but the flow may become steady at large times. The current version of the DSMC code is applicable only to zero and one-dimensional flows and the older DS2V code is employed for the two-dimensional validation and demonstration cases. It is because of this temporary use of the older and well-proven program that the DS2V source code is made freely available for the first time. Most of the homogeneous flow cases are validation studies, but include internal mode relaxation studies and spontaneous and forced ignition leading to combustion in an oxygen-hydrogen mixture. The one-dimensional cases include the structure of a re-entry shock wave that takes into account electronic excitation as well as dissociation, recombination and exchange reactions. They also include a spherically imploding shock wave and a spherical blast wave. The two-dimensional and axially-symmetric demonstration cases range from a typical MEMS flow to aspects of the flow around rotating planets. Intermediate cases include the formation and structure of a combustion wave, a vacuum pump driven by thermal creep, a typical vacuum processing chamber, and the flow around a typical re-entry vehicle
Book Synopsis Nonequilibrium Gas Dynamics and Molecular Simulation by : Iain D. Boyd
Download or read book Nonequilibrium Gas Dynamics and Molecular Simulation written by Iain D. Boyd and published by Cambridge University Press. This book was released on 2017-03-23 with total page 383 pages. Available in PDF, EPUB and Kindle. Book excerpt: 7.1 Introduction -- 7.2 Rotational Energy Exchange Models -- 7.2.1 Constant Collision Number -- 7.2.2 The Parker Model -- 7.2.3 Variable Probability Exchange Model of Boyd -- 7.2.4 Nonequilibrium Direction Dependent Model -- 7.2.5 Model Results -- 7.3 Vibrational Energy Exchange Models -- 7.3.1 Constant Collision Number -- 7.3.2 The Millikan-White Model -- 7.3.3 Quantized Treatment for Vibration -- 7.3.4 Model Results -- 7.4 Dissociation Chemical Reactions -- 7.4.1 Total Collision Energy Model -- 7.4.2 Redistribution of Energy Following a Dissociation Reaction -- 7.4.3 Vibrationally Favored Dissociation Model -- 7.5 General Chemical Reactions -- 7.5.1 Reaction Rates and Equilibrium Constant -- 7.5.2 Backward Reaction Rates in DSMC -- 7.5.3 Three-Body Recombination Reactions -- 7.5.4 Post-Reaction Energy Redistribution and General Implementation -- 7.5.5 DSMC Solutions for Reacting Flows -- 7.6 Summary -- Appendix A: Generating Particle Properties -- Appendix B: Collisional Quantities -- Appendix C: Determining Post-Collision Velocities -- Appendix D: Macroscopic Properties -- Appendix E: Common Integrals -- References -- Index
