Coupled Eulerian Langrangian Analysis 1

[Newone123]

Hello everyone. I am using Abaqus software for simulating blast (in a drillhole) by using Coupled Eulerian Langrangian analysis.
I have doubt regarding extent of eulerian domain.
1.) Should my eulerian domain (consisting of explosive only) be limited to volume inside the hole or should it cover the outsides of hole also?
2.) What if my eulerian domain consists of air apart from explosive? In that case , if i assume eulerian domain to be existing outside the blasthole, then surrounding strata and air would be occupying the same space?

 

[FEA way]

The Eulerian domain should occupy the whole space in which the material (such as fluid) can be present during the analysis. Parts of it can be initially empty (defined as void). It should intersect a bit with Lagrangian regions in contact with the fluid and account for changes in the Lagrangian domain due to deformation.

 

[Newone123]

Thanks for prompt reply! This helps a lot.

My problem is that there is already strata present around explosive.
If i take the whole of eulerian domain encompassing all the strata (option 1 in attachment), then EVF value for air (outside explosive) would be incorrect as Langrangian strata and Eulerian air cannot exist at same point in space.

Whereas in case of option 2 (in attachment), after explosion i understand that air may enter into space previously occupied by strata which shall not be covered by Eulerian grid.

 

[FEA way]

Here's a quote from the documentation explaining this:

In most cases the Lagrangian part is assembled inside of the Eulerian part instance. While Lagrangian and Eulerian elements and nodes can overlap, three-dimensional Lagrangian elements cannot occupy the same space as an Eulerian material instance. Therefore, Lagrangian parts must be instanced in an area of void within the Eulerian part instance (i.e., a region with no material assignment). To model a three-dimensional Lagrangian part instance that is completely surrounded by Eulerian material, use the volume fraction tool to create an Eulerian material assignment field that includes a void region corresponding to the Lagrangian part instance.