On the Use of the Potential Flow Model
for Aerodynamic Design at Transonic Speeds
AIAA Paper 95-0436, 33rd AIAA Aerospace Sciences Meeting and Exhibit,
Jan. 10, 1995, Reno, NV
W.H. Mason
Abstract
The full potential flow model is still widely used. In this paper we provide
a new explanation of its principle shortcoming in terms that can be easily
understood by aerodynamicists. The classical nozzle problem is examined to
show that the use of the full potential shock jump precludes the influence
of back pressure in locating the jump in the nozzle. Although the difference
in properties between the potential and Rankine-Hugoniot jumps do not look to
be that different when viewed in the customary manner, an analysis by Laitone
some years ago reveals startling differences between the potential and
Rankine-Hugoniot jumps. This difference provides an improved understanding
of the failure of the full potential theory as soon as even modest shock
strengths occur. It also suggests a physical basis for the non-uniqueness
of potential solutions.
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mason@aoe.vt.edu