<DOC>
<DOCNO>
311
</DOCNO>
<TITLE>
a method for predicting the onset of buffeting and other separation
effects from wind tunnel tests on rigid models .
</TITLE>
<AUTHOR>
pearcey, h. h.
</AUTHOR>
<BIBLIO>
n.p.l. aero. 358, fm 2763. dec. 1958 .
</BIBLIO>
<TEXT>
the method is based on the observation of the divergence that occurs in
the variation of mean static pressure at the trailing edge of an aircraft
wing at the critical stage in the development of boundary-layer
separation when its influence first spreads to the trailing edge and
thereby to the overall flow .
the significance of the trailing-edge pressure variations and their
connection with the effects that separation has on the mean and unsteady
 loads is discussed for various types of separation . good prediction
can be obtained from wind-tunnel tests, or warning provided in flight,
for low-speed separations and for shock-induced ones up to the stage at
which the shock wave reaches the trailing edge . related divergences in
wake width, lift coefficient, or shock position can also be used .
pressure measurements at other isolated points often indicate the type
of separation .
certain special considerations apply for swept wings .
the various flow changes that are considered are illustrated by
schlieren photographs and described in an appendix .
</TEXT>
</DOC>
