We describe the development of a flux-limited gray radiation solver for the compressible astrophysics code, CASTRO. CASTRO uses an Eulerian grid with block-structured adaptive mesh refinement based on a nested hierarchy of logically-rectangular variable-sized grids with simultaneous refinement in both space and time. The gray radiation solver is based on a mixed-frame formulation of radiation h...

A computational approach to homogeneous nucleation is proposed based on Eulerian description of the gas phase expansion coupled with a Lagrangian approach to the cluster formation. A continuum, Euler/Navier-Stokes solver versatile advection code is used to model the gas transport, and a kinetic particle solver is developed in this work to simulate cluster nucleation and growth. Parameters in th...

We propose a relaxation framework for general fluid models which can be understood as a natural extension of the Suliciu approach in the Euler setting. In particular, the relaxation system may be totally degenerate. Several stability properties are proved. The relaxation procedure is shown to be efficient in the numerical approximation of the entropy weak solutions of the original PDEs. The num...

An efficient unstructured 3D Euler solver is parallelized on a Thinking Machine Corporation Connection Machine 5, distributed memory computer with vectorizing capability. In this paper, the SIMD strategy is employed through the use of the CM Fortran language and the CMSSL scientific library. The performance of the CMSSL mesh partitioner is evaluated and the overall efficiency of the parallel fl...

Results from outdoor acoustic measurements performed in a railway site near Reims in France in May 2010 are compared to those obtained from a finite-difference time-domain solver of the linearized Euler equations. During the experiments, the ground profile and the different ground surface impedances were determined. Meteorological measurements were also performed to deduce mean vertical profile...

The Molten Salt Fast Reactor (MSFR) is a nuclear reactor concept under development in the framework of H2020-Euratom project SAMOSAFER. Given its peculiar characteristics as circulating-fuel reactor, new simulation tools need to be developed and tested for study. In this work, multiphysics solver previously OpenFOAM extended with functionalities analysis design. main focus modelling behavior Ga...

A solution adaptive scheme with directional multigrid for viscous computations on hybrid grids is presented. The ow domain is discretized with prismatic and tetrahedral elements. The use of hybrid grid enables the solver to compute accurate solutions with relatively less memory requirement than a fully unstructured grid. Further, employing prisms to discretize the full Navier-Stokes equations a...

An integrated computational  uid dynamics (CFD) and computational structural dynamics (CSD) method is developed for the simulation and prediction of  utter. The CFD solver is based on an unsteady, parallel, multiblock, multigrid Ž nite volume algorithm for the Euler/Navier–Stokes equations. The CSD solver is based on the time integration of modal dynamic equations extracted from full Ž nite e...

Detonation simulation is one of the computationally most challenging hyperbolic problems of practical interest. The source terms from detailed non-equilibrium chemistry are usually stiff and introduce non-neglectable scales typically not present in purely hydrodynamic calculations. This paper outlines all components of an efficient solution strategy. Emphasis is put on the description of the em...