Analysis of the relation between skin morphology and local flow conditions for a fast-swimming dolphin

Abstract

The dolphin skin close to the anisotropic compliant wall design could potentially reduce the friction drag. The goal of this work was to study the relation between local flow conditions around dolphin model and parameters of skin morphology relevant in flow/skin interface. Three-dimensional CAD models presenting authentic geometry of fast-swimming common dolphin Delphinus delphis and low-swimming harbor porpoise Phocaena phocaena were constructed. CFD study of the flow parameters were carried out for the natural range of dolphin swimming velocities. The results of this study allow to conclude that the stream-wise variability of the dolphin skin structure appears to be associated with the streamlined body geometry and corresponding gradients of the velocity and pressure rather than with specific local Re numbers. The hypotheses on different optimal conditions for potential drag-reducing properties of dolphin skin are proposed. © 2012 Springer Berlin Heidelberg.