push vs pull vis a vis rudders
nice, Keith.
Wayne.B wrote:
Take a look at flow patterns through props some time. You're
assuming that all the flow past the rudder (when on the suction
side) is parallel to the keel (center) line, as it *basically* is
on the discharge side.
The intake side of the prop, however, has a cone-shaped intake
pattern, with the prop at the apex. If the rudder is at an angle
to the centerline, flow will take the path of least resistance,
and to the extent that there is impact pressure on the rudder side
with the highest aspect ratio, this will just cause
disproportionate flow around the other side, increasing impact
pressure on that side, until an equilibrium is reached. Once past
the rudder, the flow resumes its 'along the centerline' flow, so
there is no net deflection, and all 'thrust' is parallel to the
centerline.
Keith Hughes
If flow deflection takes place (rudder at angle to flow), a force is
exerted. Old news to everyone, Nobel prize not likely.
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