<DOC>
<DOCNO>
753
</DOCNO>
<TITLE>
development of a quasi-steady approach to flutter and
correlation with kernel-function results .
</TITLE>
<AUTHOR>
gravitz,s.i., laidlaw,w.r., bryce,w.w. and cooper,r.e.
</AUTHOR>
<BIBLIO>
j.ae.scs. 29, 1962, 445.
</BIBLIO>
<TEXT>
  the quasi-steady approach to flutter utilizes experimental or
theoretical steady-state aerodynamic data to arrive at increased
understanding of the flutter mechanism, and also, in many cases,
acceptably accurate quantitative flutter predictions .  circulation
lag effects are neglected, but aerodynamic damping is included
in the evaluation of the air forces .  situations requiring
the inclusion of rate aerodynamics for accurate flutter estimation
are specified .
  a quasi-unsteady approach is also discussed, in which the
approximate magnitude of the circulation lag function at flutter
is included in simple modifications of quasi-steady parameters .
  closed-form solutions are derived for the flutter characteristics
of a typical section with and without rate aerodynamics .  application
is then made to the rational flutter analysis of threedimensional
multi-degree-of-freedom lifting surfaces .
  a specific planform is evaluated in the mach-number range
from zero to two .  quasi-steady, quasi-unsteady, and kernelfunction
results are compared subsonically .  quasi-steady results
are utilized supersonically .
  primary applications of the quasi-steady approach are in the
areas of preliminary design and parameter-variation studies,
modification of more sophisticated flutter theories to force compatibility
with available steady-state data, and flutter evaluation
of complex configurations which can be rationally analyzed by
steady-state aerodynamic theories, but for which no complete
unsteady aerodynamic theories are presently available .
</TEXT>
</DOC>
