UnDiFi-2D: An unstructured discontinuity fitting code for 2D grids

UnDiFi-2D, an open source (free software) Unstructured-grid, Discontinuity Fitting code, is presented. The aim of UnDiFi-2D to model gas-dynamic discontinuities in two-dimensional (2D) flows as if they were true null thickness that bound regions the flow-field where a smooth solution governing PDEs exists. therefore needs be coupled with unstructured CFD solver used discretize within flow-field. Two different, in-house developed, solvers are also included current distribution. main features software can summarized follows: Programming language written standard Fortran 77/95; its design highly modular order enhance simplicity use, maintenance and allow coupling virtually any existing solver; Usability, enhancement In improve usability, code documentation has been carefully taken into account. git distributed versioning system adopted facilitate collaborative development; Copyrights free anyone copy, distribute, change under GNU Public License version 3. present paper manifesto first public release code. It describes currently implemented features, which result more than decade still ongoing developments. This work focused on computational techniques detailed description characteristics reported. capabilities demonstrated by means examples test cases. allows easily include codes aimed at ease reuse readability. Program title: CPC Library link program files: https://doi.org/10.17632/5hwssmc2mx.1 Licensing provisions: General License, 3 language: Fortran; developed tested Intel Compiler v. 18.0.3 gfortran. External routines: depends several libraries third-party packages corpus text. Nature problem: Numerical computation discontinuities. Solution method: Shock-fitting technique. Additional comments including restrictions unusual features: At present, validated for inviscid steady unsteady without changes number discontinuity lines interaction points. implements shock-fitting algorithm cell-vertex solvers, Arbitrary Lagrangian-Eulerian (ALE) formulation. project adopts [1], control system. A repository dedicated [2] created github [3], web-based hosting service development projects using Finally, comprehensive provided form user manual Pandoc [4]. Git, system, http://git-scm.com. documentation, https://github.com/UnDiFi/UnDiFi-2D. Github, https://github.com. M. Dominici, TUGboat 35(1) (2014) 44-50.