Friday, April 25, 2008

Results from the Wind Tunnel

Some time has been already spent analysing wind tunnel results, they can now be presented, at least partly.

Here are screen shot of drag polars, as obtained during the test.

Note that the test were repeated over the different days : it can be seen that reproductibility of the result is not garanted at low speed (V=20m/s).

The Excel file containing the summary of results versus predictions can be found here.

Thanks again to the participants for accepting their prediction to be compared to measurements from the windtunnel !

1 comment:

Anonymous said...

Matt, thanks for this great job, highly interesting

It seems that most of our predictions are optimistic at low aoa, meaning that they tend to underestimate the induced or the viscous drag. Somehow, I guess this is usually the case with all simulations. Any ideas or suggestions why this is, and how to improve the simulations ?

For instance the PLu simulation uses N=5, which I assume is the NCrit value for XFoil. Does it show that the value of 9 recommended in the xfoil manual is overestimated ?