Author Archives: ben

Comparative testing

Posted on by ben

This is a work in progress, more content will be added soon

We have a mini wind tunnel with a fairly small throat, Vasari, Ansys, openFOAM and a big wind tunnel. What are the odds that they’ll give us results that are roughly the same? Will some way of testing give vastly misleading results?

Vasari is by far the easiest to use, but it’s ready made boundary conditions don’t seem to represent real life in any particularly meaningful way.

The tests demonstrate two models run in Vasari as a means of comparing the program against a physical model in the small wind tunnel and against the CFD results of ANSYS . One is a cube built within a box matching the dimensions of the small wind tunnel and the other is a cube with only a base built into the model.

From the results of the first wind tunnel simulation it is evident that the walls have a significant effect on the wake of the cube. The second test results have similar velocity solution to the tests run by Arup in ANSYS. The results are not as close for the pressure simulation.

Little wind tunnel

Big wind tunnel

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blueCAPE tools

Posted on by ben

blueCAPE are a company that make a few CFD tools for building designers. They’ve got a tool ( gbXML2STL Exporter) that allows you to export GBXML and then convert it to CFD ready stl files. They also make a cross compiled version of openFoam so that it runs in windows (which you can get around if you use my VM), but most interestingly they are about to release a wrapper around the whole lot that seems to make things nice and easy to do!