<DOC>
<DOCNO>
1330
</DOCNO>
<TITLE>
on some fourier transforms in the theory of non-stationary
flows .
</TITLE>
<AUTHOR>
garrick,i.e.
</AUTHOR>
<BIBLIO>
proc. 5th int. cong. app. mech. 1938, j. wiley, 590.
</BIBLIO>
<TEXT>
  the growth of lift on a airfoil
starting impulsively from rest to a uniform velocity
has been given by wagner (1925) .  the
steady-state lift due to circulation on an airfoil
oscillating sinusoidally and moving with
uniform velocity has been given by theodorsen
  the present paper based essentially on the
material of n. a. c. a. report no. 629 by the
author, discusses some reciprocal relations of
the nature of fourier transforms existing between
the functions of wagner and theodorsen .
kussner (1936) has already shown that wagner's
function may be derived from theodorsen's function
.  by means of a superposition principle it
is possible to utilize these fundamental functions
to treat general problems in transient
expression which is accurate to within 2 percent
is given for wagner's function .  this expression
leads to a good approximate expression
for theodorsen's function in terms of the exponential
integral, instead of hankel functions .
an analogy is drawn between transient hydrodynamic
flows and transient electrical flows .
  kussner (1936) has introduced a function
describing the growth of lift on an airfoil entering
a sharp edged vertical gust region .  this
function bears a certain relation to wagner's
function which is briefly discussed .
</TEXT>
</DOC>
