Semi-Implicit Method for Pressure Linked Equations (SIMPLE) is an iterative solver for the Navier-Stokes equations. This implementation uses finite volume discretization, is steady-state and only supports laminar incompressible flow. I got started on implementing transient behavior and a K-epsilon turbulence model, together with other scalar transport functions almost two years ago, but had no time due to work, so I decided to upload the parts that worked to GitHub. I have been working mostly with OpenFOAM recently, rather than implementing solvers from scratch.
I haven't looked at the code carefully: I am sure there are errors, and it's badly formatted. I definitely realized I've learnt a lot over the past few years about coding and modelling. Use it at your own risk!
The code creates a domain based on a set of boundaries specified in boundaries.cpp. It then iterates until convergence with iterations.cpp, alternating between estimation of velocities and pressures.
Geometries are expressed in simple, structured Cartesian grids. To make reasonable details, quite a few cells are needed, but the results can be pretty.
The code requires Eigen for its matrices. All other requirements are standard.
For implementation details, I recommend Versteeg's An Introduction to Computational Fluid Dynamics, Patankar's Numerical Heat Transfer and Fluid Flow, and Ferziger's Computational Method for Fluid Dynamics.