OpenFOAM Airfoils

I’ve been playing with OpenFOAM recently and ended up writing my own mesher. It’s been educational to work with a code which uses unstructured meshes for once. See https://github.com/garthwhelan/openfoam-mesher-stuff for details. So far all it does is generate hexahedral meshes with Cartesian coordinates, and merge boundary faces/points if two boundary patches share the same coordinate. It’s pretty straightforward to build more complicated meshes by deforming and combining Cartesian ones. For example, C meshes for airfoils can be made by deforming a rectangular Cartesian mesh so that the right edge surrounds an airfoil and then combining the interface behind the airfoil (automatically removing the duplicate faces and faces that are now internal). O meshes would involve doing the same thing, but using the entire right edge around the airfoil and merging what were the top and bottom edges.

Ultimately, I would like to build an RC plane and be able to say some of the design was inspired by CFD simulations, but this is a tall order. I think I will make sure that I can match the information on www.airfoiltools.com for \(C_l\) and \(C_d\) for a named airfoil and then use OpenFOAM to motivate the design of the control structures.

After going through some tutorials, I tried a (very nonphysical) run with an airfoil. The graph below was generated with icoFoam using a 1m airfoil at 1m/s, and with a realistic air viscosity. The boundary conditions are probably something nonphysical. Since then I’ve moved to using the freestream boundary conditions, pisoFoam, and RANS.

Paraview is actually really nice

Author: Garth Whelan

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