Hydrodynamics of an Extinct Amphibian

The Paleozoic amphibia known as Diplocaulus, of the order Nectridia, are characterized by long tabular horns similar in planform to the wings of a modern jet airliner. Previous research on the hydrodynamics of the head were established from wind tunnel tests but with a fixed body position placed at zero incidence. The current paper examines the hydrodynamics and stability if both the head and body change incidence, in order to obtain an improved understanding of the overall hydrodynamics. It is found that the conditions would result in unstable motion indicating a high level of maneuverability. Under certain conditions of head and body orientation the situation is one of static equilibrium, assuming the drag is countered by the thrust produced by the tail. Assumptions are made regarding the densities of the body and head in order to determine buoyancy effects.