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 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 RankineHugoniot 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 RankineHugoniot 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 reation 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.
Show less  Date Issued
 1973
 PURL
 http://purl.flvc.org/fcla/dt/13559
 Subject Headings
 Shock waves, StarsDensity
 Format
 Document (PDF)
 Title
 A numerical technique for multiple shock capturing in steady, quasi onedimensional flows.
 Creator
 Brigandi, Joseph., Florida Atlantic University, Chow, Wen L.
 Abstract/Description

A numerical technique is given to capture multiple shocks in steady, quasi onedimensional 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 onedimensional 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.
Show less  Date Issued
 1990
 PURL
 http://purl.flvc.org/fcla/dt/14673
 Subject Headings
 Fluid dynamics, CompressibilityComputer programs, Shock wavesComputer programs
 Format
 Document (PDF)
 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 Pointblast 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 Pointblast explosion. L. I. Sedov's solution of Pointblast explosion and Gary A. Sod's solution of a Riemann problem have been rederived 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 Pointblast 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 Pointblast explosion. L. I. Sedov's solution of Pointblast explosion and Gary A. Sod's solution of a Riemann problem have been rederived here from one dimensional fluid dynamics equations . Both these problems have been solved by using the idea of Selfsimilarity 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.
Show less  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)