Publications
An isotropic material remap scheme for Eulerian Codes
Shock Physics codes in use at many Department of Energy (DOE) and Department of Defense (DoD) laboratories can be divided into two classes; Lagrangian Codes (where the computational mesh is (attached' to the materials) and Eulerian Codes (where the computational mesh is (fixed' in space and die materials flow through the mesh). These two classes of codes exhibit different advantages and disadvantages. Lagrangian codes are good at keeping material interfaces well defined, but suffer when the materials undergo extreme distortion which leads to severe reductions in the time steps. Eulerian codes are better able to handle severe material distortion (since the mesh is fixed the time steps are not as severely reduced), but these codes do not keep track of material interfaces very well. So in an Eulerian code the developers must design algorithms to track or reconstruct accurate interfaces between materials as the calculation progresses. However, there are classes of calculations where an interface is not desired between some materials, for instance between materials that are intimately mixed (dusty air or multiphase materials). In these cases a material interface reconstruction scheme is needed that will keep this mixture separated from other materials in the calculation, but will maintain the mixture attributes. This paper will describe the Sandia National Laboratories Eulerian Shock Physics Code known as CTH, and the specialized isotropic material interface reconstruction scheme designed to keep mixed material groups together while keeping different groups separated during the remap step.