<DOC>
<DOCNO>
379
</DOCNO>
<TITLE>
reverse flow and variational theorems for lifting surfaces
in nonstationary compressible flow .
</TITLE>
<AUTHOR>
flax,a.h.
</AUTHOR>
<BIBLIO>
j. ae. scs. 20, 1953.
</BIBLIO>
<TEXT>
  a reverse-flow theorem for compressible nonsteady flow, valid
within the limits of linearized theory, is derived .  this theorem
gives a general class of relations between linearized solutions for
lifting surfaces in direct and reverse flow .  based on the same considerations
used to establish the theorem, an adjoint variational
principle, which may be useful in approximate solutions of nonsteady
lifting surface problems, is obtained .  to illustrate the
uses of the reverse-flow theorem, it is applied to the determination
of relations between aerodynamic coefficients in direct and reverse
flow and to the obtaining of influence functions for total
lift, pitching moment, and rolling moment for a wing oscillating
with arbitrary motion and surface deformation, in terms of the
pressure distributions for simpler cases in reverse flow .
</TEXT>
</DOC>
