Comparative study of aerodynamic properties of ichthyosaur bodies

Abstract

The flow of viscous incompressible fluid around the geometric shapes corresponding to the bodies of ichthyosaurs of different evolutionary ages has been studied. The static pressure and flow velocity distributions around the bodies have been computed with the help of AnSys Fluent 2021 R2 software. It is shown that at some ‘angles of attack’ of the body to the flow there are vortices, pairs of vortices or vortex wakes, which lead to changes in the shear stress distribution along the body, that can be used by aquatic animals for purposes of sensing their environment and communicating. The hydrodynamic properties of the ichthyosaur bodies have been compared with dolphins and whales of a similar size. It is shown that in terms of aerodynamic indices there are no obvious differences between body forms of different evolutionary ages. Different species are most likely to have adapted the specifics of swimming, such as speed, angles of attack, habitation in the upper or lower layers, and others to their living conditions. The obtained results allow us to understand better the adaptational mechanisms and direction of evolution of aquatic animals.