title: Visualization of vorticity and vortices in wall-bounded turbulent flows.
abstract: This study was initiated by the scientifically interesting prospect of applying advanced visualization techniques to gain further insight into various spatio-temporal characteristics of turbulent flows. The ability to study complex kinematical and dynamical features of turbulence provides means of extracting the underlying physics of turbulent fluid motion. The objective is to analyze the use of a vorticity field line approach to study numerically generated incompressible turbulent flows. In order to study the vorticity field, we present a field line animation technique which uses a specialized particle advection and seeding strategy. Efficient analysis is achieved by decoupling the rendering stage from the preceding stages of the visualization method. This allows interactive exploration of multiple fields simultaneously, which sets the stage for a more complete analysis of the flow field. Multifield visualizations are obtained using a flexible volume rendering framework which is presented in this paper. Vorticity field lines have been employed as indicators to provide a means to identify "ejection" and "sweep" regions; two particularly important spatio-temporal events in wall-bounded turbulent flows. Their relation to the rate of turbulent kinetic energy production and viscous dissipation, respectively, have been identified.
authors.affiliation: Unik (University Graduate Center), University of Oslo, Unik, Kjeller, Norway. andershe@ifi.uio.no
authors.forename: Anders
authors.initials: A
authors.lastname: Helgeland
authors.forename: B Anders
authors.initials: BA
authors.lastname: Pettersson Reif
authors.forename: Øyvind
authors.initials: Ø
authors.lastname: Andreassen
authors.forename: Carl Erik
authors.initials: CE
authors.lastname: Wasberg
mesh_terms: D000465:Algorithms; D003196:Computer Graphics; D003198:Computer Simulation; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D016247:Information Storage and Retrieval / Q000379:methods; D008962:Models, Theoretical; D009716:Numerical Analysis, Computer-Assisted; D012212:Rheology / Q000379:methods*; D014584:User-Computer Interface