Computational Fluid Dynamics (CFD) is a fascinating subject. Overview of CFD The effects of fluid flow can be seen all around us. Calculations and models span many levels of complexity. In these first examples we consider inviscid flow. The Reynolds number (Re=ρVd/μ) is a dimensionless ratio of momentum to viscous effects. Flows having a very large Reynolds number are dominated by momentum over viscous effects.

Lake with Islands

Fork in the River

Bend in the River

More details, including free software, for these examples can be found in two of my books, Differential Equations and Numerical Calculus. Refer to the chapters on the Boundary Element Method. Some problems, though not inviscid, may be approximated in a similar way, as illustrated in this next figure:

Coal-Fired Boiler Model

More examples can be seen here inviscid flow examples.

There are several ways of treating viscous flows, which often contain rotational elements, or vortices. Vorticity is the local intensity of the flow to rotate. Adding the direction of rotation makes this a vector quantity. Some flows containing vortices are shown in the following examples:

Flow Over an Object with Angular Edges

Flow inside a closed container may be induced by sliding one or more of the sides, such at the top and/or bottom. These next two figures illustrate cavity flow:

Cavity with Four Circular Obstructions

Cavity with Three Circular Obstructions

More details on these flows (along with free software) may be found in my book, Computational Fluid Dynamics These next examples are transient solutions to the Navier-Stokes Equation, the fundamental partial differential equation describing fluid flow. The source code for these is also available inside the online CFD collection at the address listed in the Preface of the books (on the web page just above this one):

Flow over an Airfoil

Flow over 3 Airfoils

The three stacked figures above show: pressure, stream function (think streamlines), and vorticity (think rotational tendency).

Flow over a Minivan

Someone Had to Do It...

To infinity and beyond!

Yes, she's in there! CFDexamples.zip look for examples\nast2d.