Quote:
Originally Posted by aerohead
In Hoerner's book,he reports that the actual boundary layer thickness around trains,at the time of publication,could not be accurately deduced from formulas and would have to be established empirically from observation.
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Ah ha. I've read more than a couple of quotes in Hucho that seem to be generalizations, and his train comment may be another. Maybe he's missing a few qualifications there.
It makes sense to me that a relatively "short", high speed passenger train with uniform and streamlined coaches is a different animal than a mile long, jumbled up freight train, in terms of boundary layer thickness at the end car.
Efforts to "boat tail" the passenger train are worthwhile obviously.