Hello, a simple question about the Lagrangian and Eulerian descriptions of fluid flow.
When is the Lagrangian (particle point of view) useful? It seems
that the Eulerian is always the right one, since velocity and pressure
are fields.....
thanks !
influx
Forums
Hi
Eulerian is useful for fliud analysis but Lagrangian is usefull for metalforming mostly. but the mixture of Lagrangian and Eulerian is usefull for analysis of metal cutting mostly, recently ABAQUS EF 6.7 provided CEL (Coupled Eulerian Lagrangian), that is fantastic for analysis of problems that contain contact of fluid and solid
Differences in perspective
Eulerian descriptions are good for many problems, especially in hydrodynamics, but often you need to track discrete meshes, and Lagrangian descriptions are good for this.
Specifically, Eulerian implementations have difficulties in a few key areas (which Lagrangian descriptions handle well): tracking interfaces (because of the diffculties with advection of mixed quantities in a cell), capturing the arbitrary geometries (because of the inherent "rasterization" of the spatial domain), and tracking time-history data for points in a material. Eulerian, though, is very good with large deformations, which many Lagrangian methods fail to handle.
Mitigating techniques, such as arbitrary mesh refinement, and hybrid techniques, such as arbitrary Lagrange Euler (ALE) coupling and general Euler-Lagrange coupling, can be used to eliminate or reduce the drawbacks from pure Eulerian (or pure Lagrangian) formulations.