That's an interesting read. It does show very well the benefits of turbulation at low Re numbers, but I suspect they structured the test in a way that was very biased toward gaining favourable results for their corrugated airfoil idea. For instance:
- Why only test against a streamline airfoil designed for high Re # and a flat plate?
- Why not test against a streamline airfoil specifically designed for use at very low Re numbers?
- Why not compare the corrugated airfoil to a low Re airfoil that had conventional turbulation strips added?
- Why only one Re number tested?
I'm guessing the single Re was due to time/budget constraints but it would have cost nothing extra to compare the corrugated airfoil against something that represented the best that traditional low Re airfoil technology had to offer.