The photo at the right shows some great condensation on a
B2 Stealth Bomber. The photo was taken by Bobbi Garcia
in an F-16 chase plane.
The physical cause of the cloud is not immediately obvious.
The image doesn't have the classic cone-shaped appearance of a
Prandtl-Glauert cloud, although a similar pattern
can be seen
According to Bobbi Garcia (private correspondence and
comments on Jeff Wilkinson's
page), the condensation would appear now and then while in level flight.
Furthermore, I couldn't see any evidence of condensation
due to delta wing vortices similar to those seen on the
Although the B2 is clearly in a banking maneuver here,
the general consensus is that the above pattern is
not connected with high lift maneuvers. I
think that a reasonable guess is that the
clouds are due in part to lift enhanced by the
Prandtl-Glauert singularity. The speed of the B2
is likely to correspond to a Mach number
of 0.6 so that the enhancement is likely to be weak.
The latter point may be the reason the
shape of the cloud is non-classical.
A strange feature of the cloud is that it seems to extend beyond the
wing surfaces. This is particularly evident in the
full-size version and a
second image which appears
Edwards Air Force Base description of the photo.
You will also notice a dark band in the cloud behind
the flying wing. This band might be due to the unusual
engine exhaust or an optical effect.