AERODYNAMICS

[Mark Shelly <mshelly@noclant.navy.mil>]

   A few thoughts on theropod aerodynamics.

MOUTHS: Restorations showing dinosaurs running full speed with their
mouths open wide when they are not close to their prey are possibly wrong.
An open mouth would help slow down a fast theropod dinosaur.  Of course,
it may have been easier to breathe this way or the intent might have been
to frighten the prey.

CRESTS: The triangular shaped flats and crests on the theropod heads over
the eyes may have had an aerodynamic purpose. These features may have
helped to control air flow around the eyes at high speeds.  This would be
especially important for those theropods that had some degree of forward
facing overlapping binocular vision such as tyrannosaurs. Too much (or
little) pressure could distort the vision.  The crests may have helped
keep excessive air pressure from building up.  The fierce looking eyebrows
on eagles may do the same thing.

SHAPE:  If bipedal dinosaurs ran fast, an aerodynamic shape would be an
advantage.  The theropod dinosaurs had this shape.  The main body shape
was like that of a torpedo or a fish. The body was held nearly parallel to
the ground as it is in birds with the legs perpendicular to their bodies.
Overall, their running posture was like that of a skier trying to increase
his speed.      Mark Shelly