AMReX-Astro / AMReX-Astro/Castro

Artificial viscosity can cause problematic species fluxes

Open
#2,228 0 comments 0 reactions 0 assignees View on GitHub

Nobody has claimed this yet.

hydro
Dominant language
C++
Stars
340
Forks
105
Avg merge
3d 8h
Merged PRs (30d)
8

Description

In some cases at sharp composition gradients, the artificial viscosity may result in a term that is larger than the local flux, and in particular can flip the sign of some of the species fluxes. This will cause problems when normalize_species_fluxes is applied.

Contributor guide

No contributing guide indexed for this repository

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by locating normalize_species_fluxes and the artificial-viscosity species-flux calculation. Reproduce the issue at a sharp composition gradient and trace when the viscosity term exceeds the local flux or changes its sign. Done means the problematic flux behavior is defined and corrected without causing normalization failures.

Written by the indexing model from the issue text.

Assessment

Tech stack
cpp
Domain
hpc
Issue type
Bug
Difficulty
5/5
Estimated time
Over a week
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
25/100

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.