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riblets and gas flow
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Posted by: techman
I found riblets at NASA's web site http://www.jsc.nasa.gov/er/seh/spinoff.html (1/2 way down long page) and they improve flow by reducing drag. Have these ever been considered in engine applications, or are alternate but equivalent measures already used?
Posted by: Sean Hilbert
Research on riblets and drag reduction has been around for awhile. While I was doing my grad work on two-stroke engines, my major professor (a guy named R.E. Falco) had a grant from NASA to do some of the initial riblet research. Falco's theory was that fish's scales and birds' feathers were actually drag reduction features. His thought was that at the edge of a feather or scale a minute eddy current was set up...This eddy creates a low pressure region and helps the boundary layer stick closer to the moving body...and a thinner boundary layer results in lower drag. This theory also explains why dimples are used on a golf ball to make it fly further.
Needless to say...the racing community was not far behind in looking for applications. I have seen several Nascar cylinder heads with dimples and ridges in strategic locations. I also spotted some dimples in the intake ports of a Harley Superbike engine several years ago.
This is a great example of rapid technology transfer from a university research setting to the race track!
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