A LAGRANGIAN SCHEME FOR THE ANIMATION OF UNSTEADY SEPARATION

A procedure for animating unsteady-separation phenomena, from an impul sive start to the onset of a viscous eruption, is described in this st udy. The animation is carried out using a lagrangian technique because this type of approach is the most natural scheme for computing and vi sualizing both the displacement and viscous deformation of the fluid. Furthermore, the lagrangian approach is a very effective and accurate scheme for numerical resolution of the fluid flow as it proceeds to an eruptive state. Detailed descriptions of the algorithm and animation strategy are provided, and a sequence of images of unsteady separation , through to the time of boundary-layer breakdown, is given.