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SOME PROPERTIES OF DETONATION WAVES IN DENSE STELLAR MATERIAL
Title
SOME PROPERTIES OF DETONATION WAVES IN DENSE STELLAR MATERIAL.
Creator
MARROQUIN, ADRIAN, Florida Atlantic University
Abstract/Description
The time history of the abundances of 13 nuclei and the thermodynamic and hydrodynamic variables in the burning zone of a detonation wave were numerically followed in detail by coupling a nuclear reaction network to the Rankine-Hugoniot relations and accurate equations of state. A number of computations were performed for material with initial densities and temperatures in the range 10^9
Show moreThe time history of the abundances of 13 nuclei and the thermodynamic and hydrodynamic variables in the burning zone of a detonation wave were numerically followed in detail by coupling a nuclear reaction network to the Rankine-Hugoniot relations and accurate equations of state. A number of computations were performed for material with initial densities and temperatures in the range 10^9 < p < 10^11(g/cm^3) and 3 x 10^8 K, respectively, and compositions consisting of C^12 and O^16, and O^16, Mg^24, and Si^28. From such computations it is concluded that: (1) the nuclear rea-tion rate doubling timescale approximation gives an accurate nuclear burning timescale, (2) the propagation of a detonation wave fueled by O^16 at very high densities is virtually assured, (3) the correct energy release is obtained assuming nuclear statistical equilibrium behind the detonation wave, and this latter assumption is good, (4) the Chapman- Jouguet hypothesis is adequate in spite of the fact that the actual form of the detonation wave is more likely that of a weak detonation.
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Date Issued
1973
PURL
http://purl.flvc.org/fcla/dt/13559
Subject Headings
Shock waves, Stars--Density
Format
Document (PDF)
numerical technique for multiple shock capturing in steady, quasi one-dimensional flows
Title
A numerical technique for multiple shock capturing in steady, quasi one-dimensional flows.
Creator
Brigandi, Joseph., Florida Atlantic University, Chow, Wen L.
Abstract/Description
A numerical technique is given to capture multiple shocks in steady, quasi one-dimensional flows by solving the Euler equations from a sequence of implicit/explicit solutions for the Riemann variables. A supersonic wind tunnel with a variable area diffuser is analyzed with the results compared to exact solutions. Examples are given with both one and two standing shocks. The technique given is an extension of Moretti's scheme for a single discontinuity in a De Laval nozzle. It is shown that...
Show moreA numerical technique is given to capture multiple shocks in steady, quasi one-dimensional flows by solving the Euler equations from a sequence of implicit/explicit solutions for the Riemann variables. A supersonic wind tunnel with a variable area diffuser is analyzed with the results compared to exact solutions. Examples are given with both one and two standing shocks. The technique given is an extension of Moretti's scheme for a single discontinuity in a De Laval nozzle. It is shown that this efficient technique is easily adaptable and is equally accurate for multiple discontinuities as it is for a single discontinuity.
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Date Issued
1990
PURL
http://purl.flvc.org/fcla/dt/14673
Subject Headings
Fluid dynamics, Compressibility--Computer programs, Shock waves--Computer programs
Format
Document (PDF)
Subjecting the CHIMERA supernova code to two hydrodynamic test problems, (i) Riemann problem and (ii) Point blast explosion
Title
Subjecting the CHIMERA supernova code to two hydrodynamic test problems, (i) Riemann problem and (ii) Point blast explosion.
Creator
Ahsan, Abu Salah M., Charles E. Schmidt College of Science, Department of Physics
Abstract/Description
A Shock wave as represented by the Riemann problem and a Point-blast explosion are two key phenomena involved in a supernova explosion. Any hydrocode used to simulate supernovae should be subjected to tests consisting of the Riemann problem and the Point-blast explosion. L. I. Sedov's solution of Point-blast explosion and Gary A. Sod's solution of a Riemann problem have been re-derived here from one dimensional fluid dynamics equations . Both these problems have been solved by using the idea...
Show moreA Shock wave as represented by the Riemann problem and a Point-blast explosion are two key phenomena involved in a supernova explosion. Any hydrocode used to simulate supernovae should be subjected to tests consisting of the Riemann problem and the Point-blast explosion. L. I. Sedov's solution of Point-blast explosion and Gary A. Sod's solution of a Riemann problem have been re-derived here from one dimensional fluid dynamics equations . Both these problems have been solved by using the idea of Self-similarity and Dimensional analysis. The main focus of my research was to subject the CHIMERA supernova code to these two hydrodynamic tests. Results of CHIMERA code for both the blast wave and Riemann problem have then been tested by comparing with the results of the analytic solution.
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Date Issued
2008
PURL
http://purl.flvc.org/FAU/172665
Subject Headings
Mathematical physics, Continuum mechanics, Number theory, Supernovae, Data processing, Shock waves, Fluid dynamics
Format
Document (PDF)