Interactive Visualization of Divergence in Unsteady Flow by Level-Set Dye Advection

Dye advection is an intuitive and versatile technique to visualize both steady and unsteady flow. Dye can be easily combined with noise-based vector field representations and is an important element in user-centric visual exploration processes. However, texture-based dye advection usually does not consider the convergence and divergence of flow to adapt the intensity of the dye color. In this paper, an extended texture transport mechanism is proposed to represent and modify the density of dye according to the convergence and divergence of the underlying flow. We show how this mechanism can be incorporated into semi-Lagrangian advection of property fields and level-set advection of dye interfaces alike. It is demonstrated how our approach for texture-based dye advection lends itself to an efficient GPU implementation and therefore facilitates interactive visualization.