Abstract:
SUMMARY
A preliminary qualitative study has been made in a
smoke tunnel of the flow around a stationary circular cylinder,
having rear jet blowing, placed in a uniform stream. Motographs
have been taken which show many interesting flow phenomena.
A knowledge of these it is hoped will aid future quantitative
studies,
It is found that when the jet is deflected downwards
at an angle to the mainstream direction boundary layer separation
is delayed around the cylinder and the cylinder develops a
lift force in addition to its drag. The delay in boundary
layer separation is suggested to be mainly the result of the
'sink effect' of the jet mixing. The lift, on :the other hand,
appears to be primarily the result of partial attainment of
stagnation pressure on both sides of the jet at exit, and is
therefore of similar origin to the ‘Thwaites’ flap. A smaller,
but no less significant, contribution to the lift arises from
the direct and in91rect effects of the jet blowing.
