ALEGRA is a multi-material, arbitrary-Lagrangian-Eulerian (ALE) code for solid dynamics being developed by the Computational Physics Research and Development Department at Sandia National Laboratories. It combines the features of modern Eulerian shock codes, such as CTH, with modern Lagrangian structural analysis codes. With the ALE algorithm, the mesh can be stationary (Eulerian) with the mate...

An improved treatment of advection is essential for atmospheric transport and chemistry models. Eulerian treatments are generally plagued with instabilities, unrealistic negative constituent values, diffusion, and dispersion errors. A higher-order Eulerian model improves one error at significant cost but magnifies another error. The cost of semi-Lagrangian models is too high for many applicatio...

This paper describes RHALE, a two and three-dimensional, multi-material, arbitrary Lagrangian-Eulerian (MMALE) shock physics code written in C++. RHALE is the successor to CTH, Sandia’s 3-D Eulerian shock physics code, and will be capable of solving problems that CTH cannot adequately address. RHALE employs a three step solution algorithm for the equations of motion: (1) a Lagrangian step capab...

We propose a robust computational method for the coupled simulation of a compressible high-speed flow interacting with a highly flexible thin-shell structure. A standard Eulerian finite volume formulation on a fixed Cartesian mesh is used for the fluid, and a Lagrangian formulation based on subdivision finite elements on an unstructured mesh is used for the shell. The fluid–shell interface on t...

The development of a hydro-mechanically coupled Coupled-Eulerian–Lagrangian (CEL) method and its application to the back-analysis vibratory pile driving model tests in water-saturated sand is presented. predicted penetration using this approach good agreement with results as well fully Lagrangian simulations. In terms pore water pressure, however, CEL simulation show slightly worse accordance c...

This review article aims to provide a comprehensive and understandable account of the theoretical foundation, modeling issues, and numerical implementation of the Lagrangian–Eulerian (LE) approach for multiphase flows. The LE approach is based on a statistical description of the dispersed phase in terms of a stochastic point process that is coupled with an Eulerian statistical representation of...

The immersed boundary method is an approach to fluid-structure interaction that uses a Lagrangian description of the structural deformations, stresses, and forces along with an Eulerian description of the momentum, viscosity, and incompressibility of the fluid-structure system. The original immersed boundary methods described immersed elastic structures using systems of flexible fibers, and eve...

Arbitrary Lagrangian Eulerian (ALE) methods have existed for several decades. However, three-dimensional multi-material arbitrary Lagrangian Eulerian (MMALE) methods for unstructured grids are relatively new. MMALE algorithms provide the framework to model sections of a simulation as either Lagrangian, ALE, or Eulerian. In addition, sections of a simulation can switch in time between mesh motio...