Getting Started
The Loci-Stream code is a product of the coupling of a CFD flow solver(Stream) to an open-source parallel-computing framework (Loci). Together the two components make up the Loci-Stream code. The Loci framework is a highly scalable framework that powers the Stream solver to run on large scale machines with thousands of processors. Loci-Stream is designed to take advantage of existing commercially available front-end technology (standard grid generators) and back-end technology (post-processing software such as Tecplot, FieldView, EnSight etc.).
Below is a diagram that shows the general workflow of using Loci-Stream at a high level. The flow is from top to bottom.
Setting Up your Workflow
The core of every Loci-Stream simulation involves a vog file and a vars file. These files might have names such as case.vog and case.vars. More information about the specifics of the vog and vars file formats can be found in the users’ manual.
If you create a minimal simulation directory you need a case.vars and case.vog file (the prefix “case” is arbitrary, and only needs to be the same between the vars and vog file names). Below shows the starting state of a working directory prior to running Loci-Stream.
The vars and vog files are generated by you at the outset of your simulation with the vars file containing the control information for the Loci-Stream solver and the vog file containing the geometry that the solver will use to generate a solution. The users’ guide and the tutorials contain examples for how to make calls to Loci-Stream to initiate the solver. As the Loci-Stream solver executes, it will generate output files, and your simulation directory will look like the following.
At this point, your simulation may have run to completion, and you may want to view your solution at a specific iteration(or timestep) number. A utility named extract is used to convert the solution output files in the output/ directory into files that can be opened and viewed in most standard scientific data visualization tools. The specifics of the arguments to provide to the extract utility are outlined in the tutorials and in the users’ manual. If your simulation needs to continue, Loci-Stream can be restarted from checkpoint files that are periodically written to the restart/ directory (the frequency of writes are controlled in the case.vars file).
This is the general workflow of using the Loci-Stream solver. More advanced applications require additional files beyond the vars and vog files, such as tabulated thermodynamic data, or reaction mechanism files, but the general process remains the same.