Overview

These pages are intended for users interested in exploring and customizing the numerical solvers and code structures to develop new thermodynamic models or numerical methods. While a deep understanding of the AMReX framework is not strictly required, it is highly recommended to familiarize yourself with how AMReX manages data structures and operations.

The code makes extensive use of templates, often employing them in unconventional ways. At its core, a basic template is used to define the number of scalar variables to be solved and their respective locations in the storage array. This template specifies numerous indicators for the position of each variable and is encapsulated in the indicies_t structure.

This foundational template is then combined with additional templates for thermodynamics, transport properties, and turbulence models (if applicable), which collectively form the closures_dt template.

This is done in prob.h, where we define a ProbClosures

typedef closures_dt<indicies_t, visc_suth_t, cond_suth_t,
                    calorifically_perfect_gas_t<indicies_t>> ProbClosures;

or

using ProbClosures = closures_dt<indicies_stat_t, visc_suth_t, cond_suth_t,
                                 calorifically_perfect_gas_t<indicies_t>>;

Each of this templates corresponds to a file (most of the times) For example the Sutherland viscosity model defined in src/cls/Transport.h

class visc_suth_t {
 private:
  // Sutherland's fit from Computational Fluid Mechanics and Heat Transfer
  Real visc_ref = 1.458e-6;
  Real Tvisc_ref = 110.4;

 public:
  AMREX_GPU_DEVICE AMREX_FORCE_INLINE Real visc(const Real& T) const {
    return visc_ref * T * sqrt(T) / (Tvisc_ref + T);
  }
};

Code Development

Use AmReX methodology

To add a new feature, the procedure is:

1. Create a branch for the new feature (locally):

$ git checkout -b AmazingNewFeature

1. Develop the feature, merging changes often from the develop branch into your AmazingNewFeature branch:

$ git commit -m "Developed AmazingNewFeature"
$ git checkout develop
$ git pull                      # fix any identified conflicts between local and remote branches of "develop"
$ git checkout AmazingNewFeature
$ git rebase develop        # fix any identified conflicts between "develop" and "AmazingNewFeature" 

1. To mare sure the feature does not break the code, run a regression test by

$ cerisse test

Similarly check for compilation across examples to prevent breaking options. In the /bin directory

$ ./checkcompilation.sh

This will test compilation across multiple examples. This will take around 10 minutes and assumes third party libraries have been installed (PelePhysics and CGAL)