The effects of closing angle and proximity of free surface on separation on a submerged body of revolution
Abstract
This thesis conducts an experimental investigation of
the effects on separation of the closing angle of the stern
section, the depth of submergence or proximity of the free
surface, and the speed of a submerged body of revolution.
The results of this investigation are then compared to the
results obtained from two existing theoretical criteria for
the prediction of the separation point on such bodies in
turbulent flow. The point of separation is observed experimentally
by photographing dye-flow patterns over the stern
of the model at three speeds from .75 to 1.7 knots, at three
depths of submergence corresponding to surfaced, near surface
and fully submerged conditions for five different body
stern shapes increasing in streamlining from a blunt hemisphere
to a finely shaped almost pointed section. Equivalent
body profiles to the outside of the turbulent boundary layer
displacement thickness are computed and potential flow pressure-
velocity distributions based upon the equivalent profiles
are calculated and used in evaluating the separation
criteria.
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