Flow visualization research has experienced dramatic changes during the last decade, also resulting from advances in simulation technology. While steady-state inviscid solutions of the Euler equations were widely used one decade ago, it is nowadays common practice to investigate problems based on the full time-dependent Navier-Stokes equations. This has triggered new research of visualization techniques that reveal the advection of virtual tracers in time-dependent flow. This talk will present physically-based interactive dye advection and show how it can be extended to visualize the advection-diffusion processes inherent in flow simulations that include additional quantities such as heat. Our second example represents a recent discovery in the field of time-dependent vector field topology. While different approaches have been researched in the last decade, it turns out that such a topology can be obtained by simply replacing the role of streamlines by streak lines in the original concept.