<DOC>
<DOCNO>
314
</DOCNO>
<TITLE>
simplified method for determination of the critical
height of distributed roughness particles for boundary
layer transition at mach numbers from 0 to 5.
</TITLE>
<AUTHOR>
braslow,a.l. and knox,e.c.
</AUTHOR>
<BIBLIO>
naca tn.4363, 1958.
</BIBLIO>
<TEXT>
  a simplified method has been devised for determination of the
critical height of three-dimensional roughness particles required to
promote premature transition of a laminar boundary layer on models of
airplanes or airplane components in a wind tunnel with zero heat transfer
.  a single equation is derived which relates the roughness height
to a reynolds number based on the roughness height and on local flow
conditions at the height of the roughness, and charts are presented
from which the critical roughness height can be easily obtained for
mach numbers from 0 to 5 .  a discussion of the use of these charts is
presented with consideration of various model configurations .
  the method has been applied to various types of configurations in
several wind-tunnel investigations conducted by the national advisory
committee for aeronautics at mach numbers up to 4, and in all cases
the calculated roughness height caused premature boundary-layer transition
for the range of test conditions .
</TEXT>
</DOC>
