<DOC>
<DOCNO>
608
</DOCNO>
<TITLE>
aerodynamic noise in supersonic wind tunnels .
</TITLE>
<AUTHOR>
laufer, j.
</AUTHOR>
<BIBLIO>
j. aero. sc. v. 28, sept. 1961 .
</BIBLIO>
<TEXT>
hot-wire measurements in the free stream of a supersonic wind tunnel
were made in the mach number range of 1.6 to 5.0 . it is shown that the
mass-flow fluctuations increase very rapidly with increasing mach number
. if the fluctuation field is assumed to consist of sound waves-dash
an assumption that is consistent with the measurements-dashthe sound
intensity is approximately proportional to m, within the range of the
experiments . furthermore, the orientation of the field is found to be
different from the mach line direction,. it corresponds to a soundsource
velocity of approximately one-half the free-stream velocity for
the higher mach numbers . it is shown that the turbulent boundary layer
along the nozzle and the tunnel walls is responsible for this sound
field .
</TEXT>
</DOC>
