I am pretty sure that any hydraulic engineer wants to have a code for integrating Navier-Stokes equations over a complex domain. Fortunately there are some cool guys who share their work.This is what Navier-Stokes Solver (Navier2d) is: a Matlab solver of motion of incompressible fluids via a solution of the Navier-Stokes equations in 2-D domains, discretized by unstructured meshes. Only the incompressible equations are solved, so the flow speed has to be sufficiently low (Mach Number < 0.3).

Navier2d includes three options:

  1.  Normal – solves the Navier-Stokes equations for the velocity and pressure fields.
  2. Tracer – as above, but also solves an additional transport equation for a scalar quantity within the flow.
  3. Thermal – as above, but treats the scalar tracer field as the temperature of the fluid and includes buoyancy terms in the momentum equations. This allows the solution of coupled thermal problems (like thermal convection).

In Navier2d no turbulence model is implemented. At high Reynolds numbers this becomes very important, because it is necessary to account for sub-grid scale effects. This limitation can be by-passed reducing the grid size, at least in domain zones where the momentum exchanges are important.

Navier2d supports three Boundary Condition types: known velocities and two outflow types.

You need a mesh generator to create general domains. The same author created a 2-D mesh generator (MESH2D). Details of mesh2D can be found here.

Navier2d is Copyright (C) 2005-2006 Darren Engwirda (d_engwirda@hotmail.com). Navier2d is distributed under the GNU GPL.