<DOC>
<DOCNO>
1289
</DOCNO>
<TITLE>
numerical technique to lifting surface theory for calculation
of unsteady aerodynamic forces due to continuous sinusoidal
gusts on several wing planforms at sobsonic speeds .
</TITLE>
<AUTHOR>
murrow,h.n., pratt,k.g. and drischler,j.a.
</AUTHOR>
<BIBLIO>
nasa tn.d1501, 1963.
</BIBLIO>
<TEXT>
  a numerical lifting-surface method has
been used to calculate direct gust
forces and moments on wings of several
planforms .  the gust velocities are continuous
and vary sinusoidally in the stream
direction and are also uniform across
the wing span .  the procedure has the
advantage of rapid machine calculation and
includes the effects of wing planform,
nonsteady subsonic flow, and induced flow
effects .  the method provides for calculation
of gust forces on a basis consistent
with that for the calculation of forces
due to motion and deformation .  the
results include the in-phase and quadrature
components of the following
quantities ..  (a) spanwise distribution of
section lift coefficient, (b) total
lift coefficient, and (c) total pitching-moment
coefficient .  in addition, generalized
gust forces on approximate fundamental
cantilever bending modes (parabolic)
are also included .  results have been
obtained for 60 and 75 delta wings,
ratio 11.60, and an unswept wing of aspect
ratio 6.00 .  conditions for which calculations
were made include two mach numbers
reduced-frequency range of 0 to 1.0 .  the
direct gust forces and moments are in
forms suitable to be inserted in equations
of motion used in the calculation of
the dynamic responses of flexible lifting
vehicles to random turbulence and to be
compared with results from other methods .
</TEXT>
</DOC>
