Reactive flows encompass a broad range of physical phenomena, interacting over many different time and space scales. Such flows occur in combustion, chemical lasers, the earth's oceans and atmosphere, and stars and interstellar space. Despite the obvious physical differences in these flows, there is a striking similarity in the forms of their descriptive equations. Thus, the considerations and procedures for constructing numerical models of these systems are also similar, and these similarities can be exploited. Moreover, using the latest technology, what were once difficult and expensive computations can now be done on desktop computers. This book takes account of the explosive growth in computer technology and the greatly increased capacity for solving complex reactive flow problems that have occurred since the first edition of Numerical Simulation of Reactive Flow was published in 1987. It presents algorithms useful for reactive flow simulations, describes trade-offs involved in their use, and gives guidance for building and using models of complex reactive flows.

We numerically studied the explosion of a supernova caused by supersonic jets present in its center. The jets are assumed to be generated by a magneto-rotational mechanism when a stellar core collapses into a neutron star. We simulated the process of the jet propagation through the star, jet breakthrough, and the ejection of the supernova envelope by the lateral shocks generated during jet propagation. The end result of the interaction is a highly nonspherical supernova explosion with two high-velocity jets of material moving in polar directions, and a slower moving, oblate, highly distorted ejecta containing most of the supernova material.

PUbic( repo tnq burden for this C0144711011o t informaton i$ estimated toApproved for public release; distribution unlimited. ABSTRACT (Maximum 200 words)Fluid dynamic turbulence is one of the most challenging computational physics problems because of the extremely wide range of time and space scales involved, the strong nonlinearity of the government equations, and the many practical and important applications. While most linear fluid instabilities are well understood, the nonlinear interactions among them makes even the relatively simple limit of homogeneous isotropic turbulence difficult to treat physically, mathematically, and computationally. Turbulence is modeled computationally by a twostage bootstrap process. The first stage, Direct Numerical Simulations, attempts to resolve the relevant physical time and space scales but its application is limited to diffusive flows with a relatively small Reynolds number (Re). Using Direct Numerical Simulation to provide a database, in turn, allows calibration of phenomenological turbulence models for engineering applications. Large Eddy Simulation incorporates a form of turbulence modelling applicable when the large-scale flows of interest are intrinsically time dependent, thus throwing common statistical models into question. A promising approach to Large Eddy Simulation involves the use of high-resolution monotone computational fluid dynamics algorithms such as Flux-Corrected Transport or the Piecewise Parabolic Method which have intrinsic subgrid turbulence models coupled naturally to the resolves scales in the computed flow. The physical considerations underlying and evidence supporting this Monotone Integrated Large Eddy Simulation approach are discussed.