<DOC>
<DOCNO>
218
</DOCNO>
<TITLE>
intensity, scale and spectra of turbulence in mixing
region of free subsonic jet .
</TITLE>
<AUTHOR>
laurence,j.
</AUTHOR>
<BIBLIO>
naca r1292, 1956.
</BIBLIO>
<TEXT>
  the intensity of turbulence, the longitudinal and lateral correlation
coefficients, and the spectra of turbulence in a 3.5-inchdiameter
free jet were measured with hot-wire anemometers at
exit mach numbers from 0.2 to 0.7 and reynolds numbers from
  the results of these measurements show the following ..  (1)
near the nozzle (distances less than 4 or 5 jet diam downstream
of the nozzle) the intensity of turbulence, expressed as percent
of core velocity, is a maximum at a distance of approximately
increasing mach and or reynolds number .  at distances greater
than 8 jet diameters downstream of the nozzle, however, the
maximum intensity moves out and decreases in magnitude until
the turbulence-intensity profiles are quite flat and approaching
similarity .  (2) the lateral and longitudinal scales of turbulence
are nearly independent of mach and or reynolds number
and in the mixing zone near the jet vary proportionally with
distance from the jet nozzle .  (3) farther downstream of the
jet the longitudinal scale reaches a maximum and then decreases
approximately linearly with distance .  (4) near the nozzle the
lateral scale is much smaller than the longitudinal and does not
vary with distance from the centerline, while the longitudinal
scale is a maximum at a distance from the centerline of about
mum moves out from the centerline .  (6) a statistical analysis
of the correlograms and spectra yields a /scale/ which, although
different in magnitude from the conventional, varies similarly
to the ordinary scale and is easier to evaluate .
</TEXT>
</DOC>
