Good info. Thanks, Elon, Dave.
Now, anybody with a flow bench wanna test a manifold from smooth to
gritty? That should be a great se of data. Any old manifold would work.
Polish it to a mirror, take data, add some git with glue and sand, make
another run, change grit and do it again...
I don't have a flow bench....
Elon, any idea where the thesis paper can be obtained? Data is really good.
mayf
______________________________
drmayf
Worlds Fastest Sunbeam, period.
204.913 mph flying mile
210.779 mph exit speed
On 6/5/2011 5:19 PM, Kirkwood wrote:
> The founder of Go Power did this work while working on his PhD at Stanford
> about 60 years ago. He was an avid go-carter and the emphasis in those days
> was "port and polish" . . . with emphasis based on "polish". He debunked
> that myth in his thesis.
>
>
>
> You are correct in that here is a boundary layer. That layer also has
> "static cling" LOL, or more technically "stiction", capillary attraction, or
> call what you want, with the passage wall. The thickness of this dead-zone
> layer is proportional to velocity. But, regardless of velocity, the flow
> attached to the wall is essentially zero. So any protrusion in that area is
> irrelevant. Only discontinuities sticking up through the boundary layer
> influences flow. IIRC, anything with 60 grit (about 1/16") is fine. As Dave
> has already indicated. I think some studies showed even a 120RMS had little
> influence on flow.
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