Meeting Abstract
Hydrodynamic performance is an important factor in the living and non-living realms, and has been actively studied across many domains ranging from the swimming of living organisms to the propulsion of aircrafts and airfoils. Because of the difficulty inherent in measuring hydrodynamic factors (such as drag coefficients) or performance directly, biological studies often use morphological proxies to measure such hydrodynamic performance. Unfortunately, the utility and accuracy of many of these proxies have yet to be validated for many species. Turtle shells may be used as a model system to study hydrodynamic behavior and assess the ability of such proxies to successfully measure hydrodynamic drag. We designed and printed multiple three-dimensional models shells, corresponding to the major axes of variation among turtle shells. We then measured drag on these shell models in the Bucknell University wind tunnel, and used regression to analyze the relationships between the measured drag coefficients and various proxies which have been proposed for hydrodynamic performance. Our preliminary analyses showed that none of the given proxies accurately predict changes in the drag coefficient among variously shaped model shells. It is therefore possible that the usage of such common proxies does not provide useful information concerning hydrodynamic performance in organisms. Further research regarding the relationship between hydrodynamic performance and more complex, possibly organism-specific, aspects of shape may allow us to develop more accurate predictors of drag.
