A Way to understand Complex Flows suggested by Vortex Flows

Abstract

In this paper, it is described that the view point of Lagrangian observation is usually more suitable than that of Eulerian observation for understanding of complex and unsteady vortex -flows. In order to investigate separation of boundary layers and formation of vortices, knowledge of physical meanings of vorticitiy is important. Fundamental factors in vortex fluid dynamics and essential concept of vortex method are explained from the view point of Lagrangian observation. Furthermore, results of numerical experience of starting flow vortex formation from an aerofoil and vortical flow around a swimming fish are introduced.