Analysis of vortex populations in turbulent wall-bounded flows

A method for characterizing cross-sections of vortices in turbulent flows

“…First of all, when analysing three-dimensional vortices, a cross-sectional plane needs to be chosen and this is complicated by the fact that the local vorticity vector is not necessarily aligned with the direction of the vortex because of shearing motions (see Gao et al (2011) for a detailed discussion on this issue). Another difficulty is that vortex cross-sections have many different geometrical shapes and vorticity distributions.…”

“…However when only planar data is available, circulation offers the advantage of being a measure of the strength of a vortex that is independent of the plane orientation, contrary to vorticity and k ci . Gao et al (2011) characterize vortices in streamwise-spanwise planes of canonical turbulent wall-bounded flows by employing several datasets (DNS and dual-plane PIV). By assuming that vortex orientation at a given streamwise-spanwise plane intersection is the direction of the real eigenvector of rũ (full 3D tensor), they calculate vortex circulation with a surface integral in the streamwise-spanwise plane but using the vorticity component parallel to the orientation of this eigenvector and an area equivalent to the area perpendicular to the eigenvector.…”

From ignition to stable combustion in a cavity flameholder studied via 3D tomographic chemiluminescence at 20 kHz

“…Progress to extend PLIF and PIV techniques for high-speed 3D measurements has also been reported. Examples include the PLIF measurements at several locations by scanning the excitation laser sheet at ~ 1 kHz [19,20], and 3D three-component velocity measurements by combining PIV with tomography [21][22][23].…”