Average corotation of line segments near a point and vortex identification

0398283 - ÚH 2014 RIV US eng J - Článek v odborném periodiku
Kolář, Václav - Šístek, Jakub - Cirak, F. - Moses, P.
Average corotation of line segments near a point and vortex identification.
AIAA Journal. Roč. 51, č. 11 (2013), s. 2678-2694. ISSN 0001-1452. E-ISSN 1533-385X
Grant CEP: GA AV ČR IAA200600801
Institucionální podpora: RVO:67985874 ; RVO:67985840
Klíčová slova: vortices * vortex identification * vortical structures
Kód oboru RIV: BK - Mechanika tekutin; BA - Obecná matematika (MU-W)
Impakt faktor: 1.165, rok: 2013

An easy-to-interpret kinematic quantity measuring the average corotation of material line segments near a point is introduced and applied to vortex identification. At a given point, the vector of average corotation of line segments is defined as the average of the instantaneous local rigid-body rotation over “all planar cross sections” passing through the examined point. The vortex-identification method based on average corotation is a one-parameter, region-type local method sensitive to the axial stretching rate as well as to the inner configuration of the velocity gradient tensor. The method is derived from a well-defined interpretation of the local flow kinematics to determine the “plane of swirling” and is also applicable to compressible and variable-density flows. Practical application to direct numerical simulation datasets includes a hairpin vortex of boundary-layer transition, the reconnection process of two Burgers vortices, a flow around an inclined flat plate, and a flow around a revolving insect wing. The results agree well with some popular local methods and perform better in regions of strong shearing.
Trvalý link: http://hdl.handle.net/11104/0225842